Review. Kinetic Energy Work Hooke s s Law Potential Energy Conservation of Energy Power 1/91

Size: px
Start display at page:

Download "Review. Kinetic Energy Work Hooke s s Law Potential Energy Conservation of Energy Power 1/91"

Transcription

1 Review Kinetic Energy Work Hooke s s Law Potential Energy Conservation of Energy Power 1/91

2 The unit of work is the A. Newton B. Watt C. Joule D. Meter E. Second 2/91

3 The unit of work is the A. Newton B. Watt C. Joule D. Meter E. Second 3/91

4 If you push an object with 3 times the force and 3 times the distance, you do A. The same amount of work B. 3 times the work C. 6 times the work D. 9 times the work E. 27 times the work 4/91

5 If you push an object with 3 times the force and 3 times the distance, you do A. The same amount of work B. 3 times the work C. 6 times the work D. 9 times the work E. 27 times the work W = Fx cosθ 5/91

6 Kinetic Energy = A. B. C. D. E. mv ma 2 m v 1 mv 2 2 mc 2 6/91

7 Kinetic Energy = A. B. C. D. E. mv ma 2 m v 1 mv 2 2 mc 2 7/91

8 An object that has kinetic energy must be A. at rest B. falling C. moving D. accelerating E. elevated 8/91

9 An object that has kinetic energy must be A. at rest B. falling C. moving D. accelerating E. elevated 9/91

10 Which has greater kinetic energy, a car moving at 30km/h or a half-as as- massive car moving at 60 km/h? A. The 30km/h car B. The 60km/h car C. They both have the same kinetic energy 10/91

11 Which has greater kinetic energy, a car moving at 30km/h or a half-as as- massive car moving at 60 km/h? A. The 30km/h car B. The 60km/h car C. They both have the same kinetic energy K K K = = = m v ( ) 1 2 m v 2 1 m ( ) ( 1 2v = m )( 4) v /91

12 In which of the diagrams below is non-zero work being done? A B C Force Displacement A. A B. B C. C D. A and B E. A and C F. A, B, and C 12/91

13 In which of the diagrams below is non-zero work being done? A B C Force Displacement A. A B. B C. C D. A and B E. A and C F. A, B, and C 13/91

14 Is it possible to do work if there is no motion? A. Yes, as long as a force is present. B. Yes, since motion is relative. C. No, because an object that is not moving has no energy. D. No, because of how work is defined. 14/91

15 Is it possible to do work if there is no motion? A. Yes, as long as a force is present. B. Yes, since motion is relative. C. No, because an object that is not moving has no energy. D. No, because of how work is defined. 15/91

16 In which case is work being done by gravity? A. A meteor heading towards earth B. A spaceship lifting off the earth C. A satellite in orbit around the earth D. A and B E. All of the above F. None of the above 16/91

17 In which case is work being done by gravity? A. A meteor heading towards earth B. A spaceship lifting off the earth C. A satellite in orbit around the earth D. A and B E. All of the above F. None of the above 17/91

18 If there is only one non-zero force acting on an object then which is possible for the Kinetic Energy? I. Increase II. Decrease III. Stay constant A. I B. I and II C. II and III D. I and III E. I, II, and III 18/91

19 If there is only one non-zero force acting on an object then which is possible for the Kinetic Energy? I. Increase II. Decrease III. Stay constant A. I B. I and II C. II and III D. I and III E. I, II, and III 19/91

20 In both cases a 5N force is applied to a moving object. In which case is more work being done by this force? A B Force Displacement A. A B. B C. Same for both cases 20/91

21 In both cases a 5N force is applied to a moving object. In which case is more work being done by this force? A B Force Displacement A. A B. B C. Same for both cases W = Fd cosθ 21/91

22 A spring, attached to a wall, has an unstretched length of 1m and a spring constant of 10N/m. The spring is pulled with a force of 10N. The length of the spring is now A. 1.1 m B. 2.0 m C m D m 22/91

23 A spring, attached to a wall, has an unstretched length of 1m and a spring constant of 10N/m. The spring is pulled with a force of 10N. The length of the spring is now A. 1.1 m B. 2.0 m C m N 10N = 10 x m 11.0 m x = x + x D m F = final k x initial x = 1.0m 23/91

24 Hooke s s Law applies to A. Springs B. Most solid materials C. Most solid materials but only up to the elastic limit of the material 24/91

25 Hooke s s Law applies to A. Springs B. Most solid materials C. Most solid materials but only up to the elastic limit of the material 25/91

26 How much work is done by the force when the object moves from 0.0m to 5.0m? A. 15.0J B. 12.5J C. 10.5J D. 4.5J Force (N) Position (m) 26/91

27 How much work is done by the force when the object moves from 0.0m to 5.0m? A. 15.0J B. 12.5J C. 10.5J D. 4.5J Force (N) Position (m) 27/91

28 Power is A. Work / distance B. Work / time C. Work X distance D. Work X time 28/91

29 Power is A. Work / distance B. Work / time C. Work X distance D. Work X time 29/91

30 Which of the paths below requires more work? A B A. A B. B C. Both the same 30/91

31 Which of the paths below requires more work? A B A. A B. B C. Both the same 31/91

32 The net work is the sum of the work from all forces. If the net work done on an object is positive then the KE must A. Increase B. Decrease C. Stay constant D. Not enough information to tell 32/91

33 The net work is the sum of the work from all forces. If the net work done on an object is positive then the KE must A. Increase B. Decrease C. Stay constant D. Not enough information to tell 33/91

34 As a planet orbits the sun, when is its kinetic energy the largest? A. Near the sun B. Far from the sun C. Its kinetic energy does not change 34/91

35 As a planet orbits the sun, when is its kinetic energy the largest? A. Near the sun B. Far from the sun C. Its kinetic energy does not change 35/91

36 The unit for power is the A. Joule B. Watt C. Newton Kg D. Kg E. S 36/91

37 The unit for power is the A. Joule B. Watt C. Newton Kg D. Kg E. S 37/91

38 The gravitational potential energy of an object depends on I. Mass II. Height III. Speed A. I B. II C. III D. I and II E. I and III F. All of the above 38/91

39 The gravitational potential energy of an object depends on I. Mass II. Height III. Speed A. I B. II C. III D. I and II E. I and III F. All of the above 39/91

40 Potential energy can be negative A. True B. False 40/91

41 Potential energy can be negative A. True B. False You can always add an arbitrary constant to any PE for convenience. For gravitational PE, you can always choose the height at which the gravitational PE=0. 41/91

42 What is the gravitational potential energy of the block? m=2 kg h=1 m A. 2 J B. 20 J C. 4 J D. You need more information before you can tell 42/91

43 What is the gravitational potential energy of the block? m=2 kg h=1 m A. 2 J B. 20 J C. 4 J The zero for potential energy is arbitrary. D. You need more information before you can tell 43/91

44 If you double the spring constant then the work necessary to compress the spring by the same amount will A. Stay constant B. Double C. Quadruple 44/91

45 If you double the spring constant then the work necessary to compress the spring by the same amount will A. Stay constant B. Double C. Quadruple U = 1 kx /91

46 An object is dragged at a speed of 10m/s along a rough surface with a force of 5N for 4m. How A. 10W B. 20W C. 50W D. 100W much power is exerted? 46/91

47 An object is dragged at a speed of 10m/s along a rough surface with a force of 5N for 4m. How A. 10W B. 20W C. 50W D. 100W much power is exerted? P= Fv 47/91

48 Assuming the gravitational potential energy of a pendulum is zero at the bottom, when is its PE = KE? A. At the top of the swing B. At the point half way up C. At the bottom of the swing D. In the lower half of the swing E. In the upper half of the swing 48/91

49 Assuming the gravitational potential energy of a pendulum is zero at the bottom, when is its PE = KE? A. At the top of the swing B. At the point half way up C. At the bottom of the swing D. In the lower half of the swing E. In the upper half of the swing 49/91

50 You shoot a rocket across the football field. At the highest point the energy is A. Purely KE B. Purely PE C. A combination of PE and KE D. Zero 50/91

51 You shoot a rocket across the football field. At the highest point the energy is A. Purely KE B. Purely PE C. A combination of PE and KE D. Zero 51/91

52 ConcepTest 6.2b Friction and Work II Can friction ever do positive work? 1) yes 2) no 52/91

53 ConcepTest 6.2b Friction and Work II Can friction ever do positive work? 1) yes 2) no Static Friction Can! Consider the case of a box on the back of a pickup truck. If the box moves along with the truck, then it is actually the force of friction that is making the box move. 53/91

54 ConcepTest 6.2c Play Ball! In a baseball game, the catcher stops a 90-mph pitch. What can you say about the work done by the catcher on the ball? 1) catcher has done positive work 2) catcher has done negative work 3) catcher has done zero work 54/91

55 ConcepTest 6.2c Play Ball! In a baseball game, the catcher stops a 90-mph pitch. What can you say about the work done by 1) catcher has done positive work 2) catcher has done negative work 3) catcher has done zero work the catcher on the ball? The force exerted by the catcher is opposite in direction to the displacement of the ball, so the work is negative. Or using the definition of work (W = F d cosθ), since θ = 180 o, then W < 0. Note that because the work done on the ball is negative, its speed decreases. Follow-up: What about the work done by the ball on the catcher? 55/91

56 ConcepTest 6.2d Tension and Work A ball tied to a string is being whirled around in a circle. What can you say about the work done by tension? 1) tension does no work at all 2) tension does negative work 3) tension does positive work 56/91

57 ConcepTest 6.2d Tension and Work A ball tied to a string is being whirled around in a circle. What can you say about the work done by tension? 1) tension does no work at all 2) tension does negative work 3) tension does positive work No work is done because the force acts in a perpendicular direction to the displacement. Or using the definition of work: W = F d cosθ since θ = 90 o, then W = 0. T v Follow-up: Is there a force in the direction of the velocity? 57/91

58 ConcepTest 6.5a Kinetic Energy I By what factor does the kinetic energy of a car change when its speed is tripled? 1) no change at all 2) factor of 3 3) factor of 6 4) factor of 9 5) factor of 12 58/91

59 ConcepTest 6.5a Kinetic Energy I By what factor does the kinetic energy of a car change when its speed is tripled? 1) no change at all 2) factor of 3 3) factor of 6 4) factor of 9 5) factor of 12 Since the kinetic energy is 1/2 mv 2, if the speed increases by a factor of 3, 3 then the KE will increase by a factor of 9. 9 Follow-up: How would you achieve a KE increase of a factor of 2? 59/91

60 ConcepTest 6.7 Work and KE A child on a skateboard is moving at a speed of 2 m/s. After a force acts on the child, her speed is 3 m/s. What can you say about the work done by the external force on the child? 1) positive work was done 2) negative work was done 3) zero work was done 60/91

61 ConcepTest 6.7 Work and KE A child on a skateboard is moving at a speed of 2 m/s. After a force acts on the child, her speed is 3 m/s. What can you say about the work done by the external force on the child? 1) positive work was done 2) negative work was done 3) zero work was done The kinetic energy of the child increased because her speed increased. This increase in KE was the result of positive work being done. Or, from the definition of work, since W = KE = KE f KE i and we know that KE f > KE in i this case, then the work W must be positive. Follow-up: up: What does it mean for negative work to be done on the 61/91 child?

62 ConcepTest 6.8a Slowing Down If a car traveling 60 km/hr can brake to a stop within 20 m, what is its stopping distance if it is traveling 120 km/hr? Assume that the braking force is the same in both cases. 1) 20 m 2) 30 m 3) 40 m 4) 60 m 5) 80 m 62/91

63 ConcepTest 6.8a Slowing Down If a car traveling 60 km/hr can brake to a stop within 20 m, what is its stopping distance if it is traveling 120 km/hr? Assume that the braking force is the same in both cases. 1) 20 m 2) 30 m 3) 40 m 4) 60 m 5) 80 m W friction = fd F d = W net = KE = 0 1/2 mv 2 thus: F d = 1/2 mv 2 Therefore, if the speed doubles, the stopping distance gets four times larger. 63/91

64 ConcepTest 6.8b Speeding Up I A car starts from rest and accelerates to 30 mph. Later, it gets on a highway and accelerates to 60 mph. Which takes more energy, the 0 30 mph, or the mph? 1) 0 30 mph 2) mph 3) both the same 64/91

65 ConcepTest 6.8b Speeding Up I A car starts from rest and accelerates to 30 mph. Later, it gets on a highway and accelerates to 60 mph. Which takes more energy, the 0 30 mph, or the mph? 1) 0 30 mph 2) mph 3) both the same The change in KE (1/2 mv 2 ) involves the velocity squared. So in the first case, we have: 1/2 m ( ) = 1/2 m (900) In the second case, we have: 1/2 m ( ) = 1/2 m (2700) Thus, the bigger energy change occurs in the second case. Follow-up: How much energy is required to stop the 60 How much energy is required to stop the 60-mph 65/91 car?

66 ConcepTest 6.9b Work and Energy II A golfer making a putt gives the ball an initial velocity of v 0, but he has badly misjudged the putt, and the ball only travels one-quarter of the distance to the hole. If the resistance force due to the grass is constant, what speed should he have given the ball (from its original position) in order to make it into the hole? 1) 2 v 0 2) 3 v 0 3) 4 v 0 4) 8 v 0 5) 16 v 0 66/91

67 ConcepTest 6.9b Work and Energy II A golfer making a putt gives the ball an initial velocity of v 0, but he has badly misjudged the putt, and the ball only travels one-quarter of the distance to the hole. If the resistance force due to the grass is constant, what speed should he have given the ball (from its original position) in order to make it into the hole? 1) 2 v 0 2) 3 v 0 3) 4 v 0 4) 8 v 0 5) 16 v 0 In traveling 4 times the distance, the resistive force will do 4 times the work. Thus, the ball s initial KE must be 4 times greater in order to just reach the hole this requires an increase in the initial speed by a factor of 2, 2 since KE = 1/2 mv 2. 67/91

68 ConcepTest 6.2a Friction and Work I A box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction? 1) friction does no work at all 2) friction does negative work 3) friction does positive work 68/91

69 ConcepTest 6.2a Friction and Work I A box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction? 1) friction does no work at all 2) friction does negative work 3) friction does positive work Friction acts in the opposite direction to the displacement, so the work is negative. Or using the f N displacement Pull definition of work: W = F d cosθ since θ = 180 o, then W < 0. mg 69/91

70 ConcepTest 6.6a Free Fall I Two stones, one twice the mass of the other, are dropped from a cliff. Just before hitting the ground, what is the kinetic energy of the heavy stone compared to the light one? 1) quarter as much 2) half as much 3) the same 4) twice as much 5) four times as much 70/91

71 ConcepTest 6.6a Free Fall I Two stones, one twice the mass of the other, are dropped from a cliff. Just before hitting the ground, what is the kinetic energy of the heavy stone compared to the light one? 1) quarter as much 2) half as much 3) the same 4) twice as much 5) four times as much Consider the work done by gravity to make the stone fall distance d: KE = W net = F d cosθ KE = mg d Thus, the stone with the greater mass has the greater KE, which is twice as big for the heavy stone. Follow-up: up: How do the initial values of gravitational PE compare? 71/91

72 ConcepTest 6.9b Work and Energy II A golfer making a putt gives the ball an initial velocity of v 0, but he has badly misjudged the putt, and the ball only travels one-quarter of the distance to the hole. If the resistance force due to the grass is constant, what speed should he have given the ball (from its original position) in order to make it into the hole? 1) 2 v 0 2) 3 v 0 3) 4 v 0 4) 8 v 0 5) 16 v 0 72/91

73 ConcepTest 6.9b Work and Energy II A golfer making a putt gives the ball an initial velocity of v 0, but he has badly misjudged the putt, and the ball only travels one-quarter of the distance to the hole. If the resistance force due to the grass is constant, what speed should he have given the ball (from its original position) in order to make it into the hole? 1) 2 v 0 2) 3 v 0 3) 4 v 0 4) 8 v 0 5) 16 v 0 In traveling 4 times the distance, the resistive force will do 4 times the work. Thus, the ball s initial KE must be 4 times greater in order to just reach the hole this requires an increase in the initial speed by a factor of 2, 2 since KE = 1/2 mv 2. 73/91

74 ConcepTest 6.10 Sign of the Energy I Is it possible for the kinetic energy of an object to be negative? 1) yes 2) no 74/91

75 ConcepTest 6.10 Sign of the Energy I Is it possible for the kinetic energy of an object to be negative? 1) yes 2) no The kinetic energy is 1/2 mv 2. The mass and the velocity squared will always be positive, so KE must always be positive. 75/91

76 ConcepTest 6.12 KE and PE You and your friend both solve a problem involving a skier going down a slope, starting from rest. The two of you have chosen different levels for y = 0 in this problem. Which of the following quantities will you and your friend agree on? 1) only B 2) only C 3) A, B, and C 4) only A and C 5) only B and C A) skier s s PE B) skier s s change in PE C) skier s s final KE 76/91

77 ConcepTest 6.12 KE and PE You and your friend both solve a problem involving a skier going down a slope, starting from rest. The two of you have chosen different levels for y = 0 in this problem. Which of the following quantities will you and your friend agree on? 1) only B 2) only C 3) A, B, and C 4) only A and C 5) only B and C A) skier s s PE B) skier s s change in PE C) skier s s final KE The gravitational PE depends upon the reference level, but the difference PE does not! The work done by gravity must be the same in the two solutions, so PE and KE should be the same. 77/91 Follow-up: Does anything change physically by the choice of y = 0?

78 ConcepTest 6.13 Up the Hill Two paths lead to the top of a big hill. One is steep and direct, while the other is twice as long but less steep. How much more potential energy would you gain if you take the longer path? 1) the same 2) twice as much 3) four times as much 4) half as much 5) you gain no PE in either case 78/91

79 ConcepTest 6.13 Up the Hill Two paths lead to the top of a big hill. One is steep and direct, while the other is twice as long but less steep. How much more potential energy would you gain if you take the longer path? 1) the same 2) twice as much 3) four times as much 4) half as much 5) you gain no PE in either case Since your vertical position (height) changes by the same amount in each case, the gain in potential energy is the same. Follow-up: How much more work do you do in taking the steeper path? Follow-up: Which path would you rather take? Why? 79/91

80 ConcepTest 6.14 Elastic Potential Energy How does the work required to stretch a spring 2 cm compare with the work required to stretch it 1 cm? 1) same amount of work 2) twice the work 3) 4 times the work 4) 8 times the work 80/91

81 ConcepTest 6.14 Elastic Potential Energy How does the work required to stretch a spring 2 cm compare with the work required to stretch it 1 cm? 1) same amount of work 2) twice the work 3) 4 times the work 4) 8 times the work The elastic potential energy is 1/2 kx 2. So in the second case, the elastic PE is 4 times greater than in the first case. Thus, the work required to stretch the spring is also 4 times greater. 81/91

82 ConcepTest 6.15 Springs and Gravity A mass attached to a vertical spring causes the spring to stretch and the mass to move downwards. What can you say about the spring s potential energy (PE s ) and the gravitational potential energy (PE g ) of the mass? 1) both PE s and PE g decrease 2) PE s increases and PE g decreases 3) both PE s and PE g increase 4) PE s decreases and PE g increases 5) PE s increases and PE g is constant 82/91

83 ConcepTest 6.15 Springs and Gravity A mass attached to a vertical spring causes the spring to stretch and the mass to move downwards. What can you say about the spring s potential energy (PE s ) and the gravitational potential energy (PE g ) of the mass? 1) both PE s and PE g decrease 2) PE s increases and PE g decreases 3) both PE s and PE g increase 4) PE s decreases and PE g increases 5) PE s increases and PE g is constant The spring is stretched, so its elastic PE increases, since PE s = 1/2 kx 2. The mass moves down to a lower position, so its gravitational PE decreases, since PE g = mgh. 83/91

84 ConcepTest 6.16 Down the Hill Three balls of equal mass start from rest and roll down different ramps. All ramps have the same height. Which ball has the greater speed at the bottom of its ramp? ) same speed for all balls 84/91

85 ConcepTest 6.16 Down the Hill Three balls of equal mass start from rest and roll down different ramps. All ramps have the same height. Which ball has the greater speed at the bottom of its ramp? ) same speed for all balls All of the balls have the same initial gravitational PE, since they are all at the same height (PE = mgh). Thus, when they get to the bottom, they all have the same final KE, and hence the same speed (KE = 1/2 mv 2 ). Follow-up: Which ball takes longer to get down the ramp? 85/91

86 ConcepTest 6.17a Runaway Truck A truck, initially at rest, rolls down a frictionless hill and attains a speed of 20 m/s at the bottom. To achieve a speed of 40 m/s at the bottom, how many times higher must the hill be? 1) half the height 2) the same height 3) 2 times the height 4) twice the height 5) four times the height 86/91

87 ConcepTest 6.17a Runaway Truck A truck, initially at rest, rolls down a frictionless hill and attains a speed of 20 m/s at the bottom. To achieve a speed of 40 m/s at the bottom, how many times higher must the hill be? 1) half the height 2) the same height 3) 2 times the height 4) twice the height 5) four times the height Use energy conservation: initial energy: E i = PE g = mgh final energy: E f = KE = 1/2 mv 2 Conservation of Energy: E i = mgh = E f = 1/2 mv 2 therefore: gh = 1/2 v 2 So if v doubles, H quadruples! 87/91

88 ConcepTest 6.21a Time for Work I Mike applied 10 N of force over 3 m in 10 seconds. Joe applied the same force over the same distance in 1 minute. Who did more work? 1) Mike 2) Joe 3) both did the same work 88/91

89 ConcepTest 6.21a Time for Work I Mike applied 10 N of force over 3 m in 10 seconds. Joe applied the same force over the same distance in 1 minute. Who did more work? 1) Mike 2) Joe 3) both did the same work Both exerted the same force over the same displacement. Therefore, both did the same amount of work. Time does not matter for determining the work done. 89/91

90 ConcepTest 6.21b Time for Work II Mike performed 5 J of work in 10 secs. Joe did 3 J of work in 5 secs. Who produced the greater power? 1) Mike produced more power 2) Joe produced more power 3) both produced the same amount of power 90/91

91 ConcepTest 6.21b Time for Work II Mike performed 5 J of work in 10 secs. Joe did 3 J of work in 5 secs. Who produced the greater power? 1) Mike produced more power 2) Joe produced more power 3) both produced the same amount of power Since power = work / time, we see that Mike produced 0.5 W and Joe produced 0.6 W of power. Thus, even though Mike did more work, he required twice the time to do the work, and therefore his power output was lower. 91/91

ConcepTest PowerPoints

ConcepTest PowerPoints ConcepTest PowerPoints Chapter 6 Physics: Principles with Applications, 6 th edition Giancoli 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for

More information

ConcepTest 6.2a Friction and Work I

ConcepTest 6.2a Friction and Work I ConcepTest 6.2a Friction and Work I A box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction? 1) friction does no work at all 2) friction does negative

More information

1) To Work or Not to Work

1) To Work or Not to Work 1) To Work or Not to Work Is it possible to do work on an object that remains at rest? 1) yes 2) no 1) To Work or Not to Work Is it possible to do work on an object that remains at rest? 1) yes 2) no Work

More information

Question 8.1 Sign of the Energy II

Question 8.1 Sign of the Energy II Question 8. Sign of the Energy II Is it possible for the gravitational potential energy of an object to be negative? a) yes b) no Question 8. Sign of the Energy II Is it possible for the gravitational

More information

Exam #2, Chapters 5-7 PHYS 101-4M MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Exam #2, Chapters 5-7 PHYS 101-4M MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Exam #2, Chapters 5-7 Name PHYS 101-4M MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The quantity 1/2 mv2 is A) the potential energy of the object.

More information

PSI AP Physics I Work and Energy

PSI AP Physics I Work and Energy PSI AP Physics I Work and Energy Multiple-Choice questions 1. A driver in a 2000 kg Porsche wishes to pass a slow moving school bus on a 4 lane road. What is the average power in watts required to accelerate

More information

What is Energy? Which has more energy? Who has more energy? 1/24/2017

What is Energy? Which has more energy? Who has more energy? 1/24/2017 What is Energy? Energy is a measure of an object s ability to cause a change in itself and/or its surroundings Read pages 61-7 Which has more energy? Who has more energy? Mississippi River Cargo Barge

More information

Work and Energy. Chapter 7

Work and Energy. Chapter 7 Work and Energy Chapter 7 Scalar Product of Two Vectors Definition of the scalar, or dot, product: A B A Alternatively, we can write: x B x A y B y A z B z Work Work Done by a Constant Force The work done

More information

Chapter 6 Energy and Oscillations

Chapter 6 Energy and Oscillations Chapter 6 Energy and Oscillations Conservation of Energy In this chapter we will discuss one of the most important and fundamental principles in the universe. Energy is conserved. This means that in any

More information

Work and Energy (Work Done by a Constant Force)

Work and Energy (Work Done by a Constant Force) Lecture 11 Chapter 7 Physics I 10.16.2013 Work and Energy (Work Done by a Constant Force) Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsi Lecture Capture: http://echo360.uml.edu/danylov2013/physics1fall.html

More information

Physics 231. Topic 5: Energy and Work. Alex Brown October 2, MSU Physics 231 Fall

Physics 231. Topic 5: Energy and Work. Alex Brown October 2, MSU Physics 231 Fall Physics 231 Topic 5: Energy and Work Alex Brown October 2, 2015 MSU Physics 231 Fall 2015 1 What s up? (Friday Sept 26) 1) The correction exam is now open. The exam grades will be sent out after that on

More information

CPS lesson Work and Energy ANSWER KEY

CPS lesson Work and Energy ANSWER KEY CPS lesson Work and Energy ANSWER KEY 1. A ball feeder slowly pushes a bowling ball up a 1-m ramp to a height of 0.5 m above the floor. Neglecting friction, what constant force must be exerted on the 5-kg

More information

S15--AP Q1 Work and Energy PRACTICE

S15--AP Q1 Work and Energy PRACTICE Name: Class: Date: S15--AP Q1 Work and Energy PRACTICE Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Rupel pushes a box 5.00 m by applying a 25.0-N horizontal

More information

Chapter 6: Work and Kinetic Energy

Chapter 6: Work and Kinetic Energy Chapter 6: Work and Kinetic Energy Suppose you want to find the final velocity of an object being acted on by a variable force. Newton s 2 nd law gives the differential equation (for 1D motion) dv dt =

More information

= 1 2 kx2 dw =! F! d! r = Fdr cosθ. T.E. initial. = T.E. Final. = P.E. final. + K.E. initial. + P.E. initial. K.E. initial =

= 1 2 kx2 dw =! F! d! r = Fdr cosθ. T.E. initial. = T.E. Final. = P.E. final. + K.E. initial. + P.E. initial. K.E. initial = Practice Template K.E. = 1 2 mv2 P.E. height = mgh P.E. spring = 1 2 kx2 dw =! F! d! r = Fdr cosθ Energy Conservation T.E. initial = T.E. Final (1) Isolated system P.E. initial (2) Energy added E added

More information

1. A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? A. 10 km B km C. 25 km D. 45 km E. 50 km

1. A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? A. 10 km B km C. 25 km D. 45 km E. 50 km Name: Physics I Mid Term Exam Review Multiple Choice Questions Date: Mr. Tiesler 1. A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? A. 10 km B. 22.5 km C. 25 km D. 45 km

More information

Lecture 10. Potential energy and conservation of energy

Lecture 10. Potential energy and conservation of energy Lecture 10 Potential energy and conservation of energy Today s Topics: Potential Energy and work done by conservative forces Work done by nonconservative forces Conservation of mechanical energy Potential

More information

1. A sphere with a radius of 1.7 cm has a volume of: A) m 3 B) m 3 C) m 3 D) 0.11 m 3 E) 21 m 3

1. A sphere with a radius of 1.7 cm has a volume of: A) m 3 B) m 3 C) m 3 D) 0.11 m 3 E) 21 m 3 1. A sphere with a radius of 1.7 cm has a volume of: A) 2.1 10 5 m 3 B) 9.1 10 4 m 3 C) 3.6 10 3 m 3 D) 0.11 m 3 E) 21 m 3 2. A 25-N crate slides down a frictionless incline that is 25 above the horizontal.

More information

Chapter 6 Work, Energy, and Power. Copyright 2010 Pearson Education, Inc.

Chapter 6 Work, Energy, and Power. Copyright 2010 Pearson Education, Inc. Chapter 6 Work, Energy, and Power What Is Physics All About? Matter Energy Force Work Done by a Constant Force The definition of work, when the force is parallel to the displacement: W = Fs SI unit: newton-meter

More information

PSI AP Physics B Dynamics

PSI AP Physics B Dynamics PSI AP Physics B Dynamics Multiple-Choice questions 1. After firing a cannon ball, the cannon moves in the opposite direction from the ball. This an example of: A. Newton s First Law B. Newton s Second

More information

Ch 5 Work and Energy

Ch 5 Work and Energy Ch 5 Work and Energy Energy Provide a different (scalar) approach to solving some physics problems. Work Links the energy approach to the force (Newton s Laws) approach. Mechanical energy Kinetic energy

More information

2. What would happen to his acceleration if his speed were half? Energy The ability to do work

2. What would happen to his acceleration if his speed were half? Energy The ability to do work 1. A 40 kilogram boy is traveling around a carousel with radius 0.5 meters at a constant speed of 1.7 meters per second. Calculate his centripetal acceleration. 2. What would happen to his acceleration

More information

Chapter 6 Work and Energy

Chapter 6 Work and Energy Chapter 6 Work and Energy Midterm exams will be available next Thursday. Assignment 6 Textbook (Giancoli, 6 th edition), Chapter 6: Due on Thursday, November 5 1. On page 162 of Giancoli, problem 4. 2.

More information

Name 09-MAR-04. Work Power and Energy

Name 09-MAR-04. Work Power and Energy Page 1 of 16 Work Power and Energy Name 09-MAR-04 1. A spring has a spring constant of 120 newtons/meter. How much potential energy is stored in the spring as it is stretched 0.20 meter? 1. 2.4 J 3. 12

More information

1 1. A spring has a spring constant of 120 newtons/meter. How much potential energy is stored in the spring as it is stretched 0.20 meter?

1 1. A spring has a spring constant of 120 newtons/meter. How much potential energy is stored in the spring as it is stretched 0.20 meter? Page of 3 Work Power And Energy TEACHER ANSWER KEY March 09, 200. A spring has a spring constant of 20 newtons/meter. How much potential energy is stored in the spring as it is stretched 0.20 meter?. 2.

More information

Name Date Hour Table

Name Date Hour Table Name Date Hour Table Chapter 3 Pre-AP Directions: Use the clues to create your word bank for the word search. Put the answer to each question with its number in the word bank box. Then find each word in

More information

Name: Class: Date: so sliding friction is better so sliding friction is better d. µ k

Name: Class: Date: so sliding friction is better so sliding friction is better d. µ k Name: Class: Date: Exam 2--PHYS 101-F08 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. You put your book on the seat next to you. When the bus stops,

More information

General Physics I Work & Energy

General Physics I Work & Energy General Physics I Work & Energy Forms of Energy Kinetic: Energy of motion. A car on the highway has kinetic energy. We have to remove this energy to stop it. The brakes of a car get HOT! This is an example

More information

Momentum, Impulse, Work, Energy, Power, and Conservation Laws

Momentum, Impulse, Work, Energy, Power, and Conservation Laws Momentum, Impulse, Work, Energy, Power, and Conservation Laws 1. Cart A has a mass of 2 kilograms and a speed of 3 meters per second. Cart B has a mass of 3 kilograms and a speed of 2 meters per second.

More information

Name Lesson 7. Homework Work and Energy Problem Solving Outcomes

Name Lesson 7. Homework Work and Energy Problem Solving Outcomes Physics 1 Name Lesson 7. Homework Work and Energy Problem Solving Outcomes Date 1. Define work. 2. Define energy. 3. Determine the work done by a constant force. Period 4. Determine the work done by a

More information

Physics 1A, Summer 2011, Summer Session 1 Quiz 3, Version A 1

Physics 1A, Summer 2011, Summer Session 1 Quiz 3, Version A 1 Physics 1A, Summer 2011, Summer Session 1 Quiz 3, Version A 1 Closed book and closed notes. No work needs to be shown. 1. Three rocks are thrown with identical speeds from the top of the same building.

More information

PHYS 101 Previous Exam Problems. Kinetic Energy and

PHYS 101 Previous Exam Problems. Kinetic Energy and PHYS 101 Previous Exam Problems CHAPTER 7 Kinetic Energy and Work Kinetic energy Work Work-energy theorem Gravitational work Work of spring forces Power 1. A single force acts on a 5.0-kg object in such

More information

Work Done by a Constant Force

Work Done by a Constant Force Work and Energy Work Done by a Constant Force In physics, work is described by what is accomplished when a force acts on an object, and the object moves through a distance. The work done by a constant

More information

D) No, because of the way work is defined D) remains constant at zero. D) 0 J D) zero

D) No, because of the way work is defined D) remains constant at zero. D) 0 J D) zero CHAPTER 6 REVIEW NAME 1) Can work be done on a system if there is no motion? A) Yes, if an outside force is provided. B) Yes, since motion is only relative. C) No, since a system which is not moving has

More information

Clicker Question: Momentum. If the earth collided with a meteor that slowed it down in its orbit, what would happen: continued from last time

Clicker Question: Momentum. If the earth collided with a meteor that slowed it down in its orbit, what would happen: continued from last time Momentum continued from last time If the earth collided with a meteor that slowed it down in its orbit, what would happen: A: It would maintain the same distance from the sun. B: It would fall closer in

More information

Physics Test 9: Work and Energy page 1

Physics Test 9: Work and Energy page 1 Name Physics Test 9: Work and Energy page 1 Multiple Choice Read each question and choose the best answer by putting the corresponding letter in the blank to the left. 1. Which of the following is a unit

More information

(A) 10 m (B) 20 m (C) 25 m (D) 30 m (E) 40 m

(A) 10 m (B) 20 m (C) 25 m (D) 30 m (E) 40 m PSI AP Physics C Work and Energy (Algebra Based) Multiple Choice Questions (use g = 10 m/s 2 ) 1. A student throws a ball upwards from the ground level where gravitational potential energy is zero. At

More information

Slide 1 / 76. Work & Energy Multiple Choice Problems

Slide 1 / 76. Work & Energy Multiple Choice Problems Slide 1 / 76 Work & Energy Multiple Choice Problems Slide 2 / 76 1 A driver in a 2000 kg Porsche wishes to pass a slow moving school bus on a 4 lane road. What is the average power in watts required to

More information

In vertical circular motion the gravitational force must also be considered.

In vertical circular motion the gravitational force must also be considered. Vertical Circular Motion In vertical circular motion the gravitational force must also be considered. An example of vertical circular motion is the vertical loop-the-loop motorcycle stunt. Normally, the

More information

Practice Test for Midterm Exam

Practice Test for Midterm Exam A.P. Physics Practice Test for Midterm Exam Kinematics 1. Which of the following statements are about uniformly accelerated motion? Select two answers. a) If an object s acceleration is constant then it

More information

4) Vector = and vector = What is vector = +? A) B) C) D) E)

4) Vector = and vector = What is vector = +? A) B) C) D) E) 1) Suppose that an object is moving with constant nonzero acceleration. Which of the following is an accurate statement concerning its motion? A) In equal times its speed changes by equal amounts. B) In

More information

Page 1. Name:

Page 1. Name: Name: 3834-1 - Page 1 1) If a woman runs 100 meters north and then 70 meters south, her total displacement is A) 170 m south B) 170 m north C) 30 m south D) 30 m north 2) The graph below represents the

More information

Old Exam. Question Chapter 7 072

Old Exam. Question Chapter 7 072 Old Exam. Question Chapter 7 072 Q1.Fig 1 shows a simple pendulum, consisting of a ball of mass M = 0.50 kg, attached to one end of a massless string of length L = 1.5 m. The other end is fixed. If the

More information

Chapter 12 Vibrations and Waves Simple Harmonic Motion page

Chapter 12 Vibrations and Waves Simple Harmonic Motion page Chapter 2 Vibrations and Waves 2- Simple Harmonic Motion page 438-45 Hooke s Law Periodic motion the object has a repeated motion that follows the same path, the object swings to and fro. Examples: a pendulum

More information

1. Which one of the following situations is an example of an object with a non-zero kinetic energy?

1. Which one of the following situations is an example of an object with a non-zero kinetic energy? Name: Date: 1. Which one of the following situations is an example of an object with a non-zero kinetic energy? A) a drum of diesel fuel on a parked truck B) a stationary pendulum C) a satellite in geosynchronous

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Common Quiz Mistakes / Practice for Final Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A ball is thrown directly upward and experiences

More information

1. (P2.1A) The picture below shows a ball rolling along a table at 1 second time intervals. What is the object s average velocity after 6 seconds?

1. (P2.1A) The picture below shows a ball rolling along a table at 1 second time intervals. What is the object s average velocity after 6 seconds? PHYSICS FINAL EXAM REVIEW FIRST SEMESTER (01/2017) UNIT 1 Motion P2.1 A Calculate the average speed of an object using the change of position and elapsed time. P2.1B Represent the velocities for linear

More information

Spring Force and Power

Spring Force and Power Lecture 14 Chapter 9 Physics I Spring Force and Power Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsi IN THIS CHAPTER, you will learn how to solve problems using two new concepts:

More information

0J2 - Mechanics Lecture Notes 2

0J2 - Mechanics Lecture Notes 2 0J2 - Mechanics Lecture Notes 2 Work, Power, Energy Work If a force is applied to a body, which then moves, we say the force does work. In 1D, if the force is constant with magnitude F, and the body moves

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. PH 105 Exam 2 VERSION A Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Is it possible for a system to have negative potential energy? A)

More information

Name St. Mary's HS AP Physics Circular Motion HW

Name St. Mary's HS AP Physics Circular Motion HW Name St. Mary's HS AP Physics Circular Motion HW Base your answers to questions 1 and 2 on the following situation. An object weighing 10 N swings at the end of a rope that is 0.72 m long as a simple pendulum.

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. PH 105 Exam 2 VERSION B Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A boy throws a rock with an initial velocity of 2.15 m/s at 30.0 above

More information

Work Energy Review. 1. Base your answer to the following question on the information and diagram below and on your knowledge of physics.

Work Energy Review. 1. Base your answer to the following question on the information and diagram below and on your knowledge of physics. Name: ate: 1. ase your answer to the following question on the information and diagram below and on your knowledge of physics. student pushes a box, weighing 50. newtons, 6.0 meters up an incline at a

More information

Lectures Chapter 6 (Cutnell & Johnson, Physics 7 th edition)

Lectures Chapter 6 (Cutnell & Johnson, Physics 7 th edition) PH 201-4A spring 2007 Work and Energy Lectures 16-17 Chapter 6 (Cutnell & Johnson, Physics 7 th edition) 1 Work and Energy: Work done by a constant force Constant pushing force F pointing in the same direction

More information

Momentum, Impulse, Work, Energy, Power, and Conservation Laws

Momentum, Impulse, Work, Energy, Power, and Conservation Laws Momentum, Impulse, Work, Energy, Power, and Conservation Laws 1. Cart A has a mass of 2 kilograms and a speed of 3 meters per second. Cart B has a mass of 3 kilograms and a speed of 2 meters per second.

More information

(A) 10 m (B) 20 m (C) 25 m (D) 30 m (E) 40 m

(A) 10 m (B) 20 m (C) 25 m (D) 30 m (E) 40 m Work/nergy 1. student throws a ball upward where the initial potential energy is 0. t a height of 15 meters the ball has a potential energy of 60 joules and is moving upward with a kinetic energy of 40

More information

WEP-Energy. 2. If the speed of a car is doubled, the kinetic energy of the car is 1. quadrupled 2. quartered 3. doubled 4. halved

WEP-Energy. 2. If the speed of a car is doubled, the kinetic energy of the car is 1. quadrupled 2. quartered 3. doubled 4. halved 1. A 1-kilogram rock is dropped from a cliff 90 meters high. After falling 20 meters, the kinetic energy of the rock is approximately 1. 20 J 2. 200 J 3. 700 J 4. 900 J 2. If the speed of a car is doubled,

More information

AP Physics 1 Work Energy and Power Practice Test Name

AP Physics 1 Work Energy and Power Practice Test Name AP Physics 1 Work Energy and Power Practice Test Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Two objects, one of mass m and the other

More information

Conservation of Energy and Momentum

Conservation of Energy and Momentum Conservation of Energy and Momentum Three criteria for Work There must be a force. There must be a displacement, d. The force must have a component parallel to the displacement. Work, W = F x d, W = Fd

More information

*************************************************************************

************************************************************************* Your Name: TEST #2 Print clearly. On the Scantron, fill out your student ID, leaving the first column empty and starting in the second column. Also write your name, class time (11:30 or 12:30), and Test

More information

Regents Physics. Physics Midterm Review - Multiple Choice Problems

Regents Physics. Physics Midterm Review - Multiple Choice Problems Name Physics Midterm Review - Multiple Choice Problems Regents Physics 1. A car traveling on a straight road at 15.0 meters per second accelerates uniformly to a speed of 21.0 meters per second in 12.0

More information

Physics Midterm Review KEY

Physics Midterm Review KEY Name: Date: 1. Which quantities are scalar? A. speed and work B. velocity and force C. distance and acceleration D. momentum and power 2. A 160.-kilogram space vehicle is traveling along a straight line

More information

Chapter 5 Force and Motion

Chapter 5 Force and Motion Chapter 5 Force and Motion Chapter Goal: To establish a connection between force and motion. Slide 5-2 Chapter 5 Preview Slide 5-3 Chapter 5 Preview Slide 5-4 Chapter 5 Preview Slide 5-5 Chapter 5 Preview

More information

(35+70) 35 g (m 1+m 2)a=m1g a = 35 a= =3.27 g 105

(35+70) 35 g (m 1+m 2)a=m1g a = 35 a= =3.27 g 105 Coordinator: Dr. W. L-Basheer Monday, March 16, 2015 Page: 1 Q1. 70 N block and a 35 N block are connected by a massless inextendable string which is wrapped over a frictionless pulley as shown in Figure

More information

Force Test Review. 1. Give two ways to increase acceleration. You can increase acceleration by decreasing mass or increasing force.

Force Test Review. 1. Give two ways to increase acceleration. You can increase acceleration by decreasing mass or increasing force. Force Test Review 1. Give two ways to increase acceleration. You can increase acceleration by decreasing mass or increasing force. 2. Define weight. The force of gravity on an object at the surface of

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) You are standing in a moving bus, facing forward, and you suddenly fall forward as the

More information

Chapters 10 & 11: Energy

Chapters 10 & 11: Energy Chapters 10 & 11: Energy Power: Sources of Energy Tidal Power SF Bay Tidal Power Project Main Ideas (Encyclopedia of Physics) Energy is an abstract quantity that an object is said to possess. It is not

More information

CHAPTER 6: IN AN ISOLATED SYSTEM, ENERGY IS TRANSFERRED FROM ONE OBJECT TO ANOTHER WHENEVER WORK IS DONE

CHAPTER 6: IN AN ISOLATED SYSTEM, ENERGY IS TRANSFERRED FROM ONE OBJECT TO ANOTHER WHENEVER WORK IS DONE CHAPTER 6: IN AN ISOLATED SYSTEM, ENERGY IS TRANSFERRED FROM ONE OBJECT TO ANOTHER WHENEVER WORK IS DONE 6.1 Work and Energy In science, work is done when a force acts over a displacement; energy is transferred.

More information

PRACTICE TEST for Midterm Exam

PRACTICE TEST for Midterm Exam South Pasadena AP Physics PRACTICE TEST for Midterm Exam FORMULAS Name Period Date / / d = vt d = v o t + ½ at 2 d = v o + v 2 t v = v o + at v 2 = v 2 o + 2ad v = v x 2 + v y 2 = tan 1 v y v v x = v cos

More information

v (m/s) 10 d. displacement from 0-4 s 28 m e. time interval during which the net force is zero 0-2 s f. average velocity from 0-4 s 7 m/s x (m) 20

v (m/s) 10 d. displacement from 0-4 s 28 m e. time interval during which the net force is zero 0-2 s f. average velocity from 0-4 s 7 m/s x (m) 20 Physics Final Exam Mechanics Review Answers 1. Use the velocity-time graph below to find the: a. velocity at 2 s 6 m/s v (m/s) 1 b. acceleration from -2 s 6 c. acceleration from 2-4 s 2 m/s 2 2 4 t (s)

More information

Slide 1 / 76. Slide 2 / 76. Slide 3 / 76. Work & Energy Multiple Choice Problems A 1,800 B 5,000 E 300,000. A Fdcos θ - μ mgd B Fdcos θ.

Slide 1 / 76. Slide 2 / 76. Slide 3 / 76. Work & Energy Multiple Choice Problems A 1,800 B 5,000 E 300,000. A Fdcos θ - μ mgd B Fdcos θ. Slide 1 / 76 Work & nergy Multiple hoice Problems 1 driver in a 2000 kg Porsche wishes to pass a slow moving school bus on a 4 lane road. What is the average power in watts required to accelerate the sports

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. PH105-007 Exam 2 VERSION A Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal

More information

B C = B 2 + C 2 2BC cosθ = (5.6)(4.8)cos79 = ) The components of vectors B and C are given as follows: B x. = 6.

B C = B 2 + C 2 2BC cosθ = (5.6)(4.8)cos79 = ) The components of vectors B and C are given as follows: B x. = 6. 1) The components of vectors B and C are given as follows: B x = 6.1 C x = 9.8 B y = 5.8 C y = +4.6 The angle between vectors B and C, in degrees, is closest to: A) 162 B) 111 C) 69 D) 18 E) 80 B C = (

More information

Mechanics. Time (s) Distance (m) Velocity (m/s) Acceleration (m/s 2 ) = + displacement/time.

Mechanics. Time (s) Distance (m) Velocity (m/s) Acceleration (m/s 2 ) = + displacement/time. Mechanics Symbols: Equations: Kinematics The Study of Motion s = distance or displacement v = final speed or velocity u = initial speed or velocity a = average acceleration s u+ v v v u v= also v= a =

More information

Newton s 3 Laws of Motion

Newton s 3 Laws of Motion Newton s 3 Laws of Motion 1. If F = 0 No change in motion 2. = ma Change in motion Fnet 3. F = F 1 on 2 2 on 1 Newton s First Law (Law of Inertia) An object will remain at rest or in a constant state of

More information

3. What type of force is the woman applying to cart in the illustration below?

3. What type of force is the woman applying to cart in the illustration below? Name: Forces and Motion STUDY GUIDE Directions: Answer the following questions. 1. What is a force? a. A type of energy b. The rate at which an object performs work c. A push or a pull d. An object that

More information

Base your answers to questions 5 and 6 on the information below.

Base your answers to questions 5 and 6 on the information below. 1. A car travels 90. meters due north in 15 seconds. Then the car turns around and travels 40. meters due south in 5.0 seconds. What is the magnitude of the average velocity of the car during this 20.-second

More information

Work and Energy. Work and Energy

Work and Energy. Work and Energy 1. Work as Energy Transfer Work done by a constant force (scalar product) Work done by a varying force (scalar product & integrals). Kinetic Energy Work-Energy Theorem Work by a Baseball Pitcher A baseball

More information

Phys101 Lectures 9 and 10 Conservation of Mechanical Energy

Phys101 Lectures 9 and 10 Conservation of Mechanical Energy Phys101 Lectures 9 and 10 Conservation of Mechanical Energy Key points: Conservative and Nonconservative Forces Potential Energy Generalized work-energy principle Mechanical Energy and Its Conservation

More information

Physics Unit 4:Work & Energy Name:

Physics Unit 4:Work & Energy Name: Name: Review and Preview We have come a long way in our study of mechanics. We started with the concepts of displacement and time, and built up to the more complex quantities of velocity and acceleration.

More information

Multiple-Choice questions

Multiple-Choice questions AP Physics I Work and Energy Multiple-Choice questions 1. A force F is at an angle θ above the horizontal and is used to pull a heavy suitcase of weight mg a distance d along a level floor at constant

More information

Work and Kinetic Energy

Work and Kinetic Energy Lecture 12 Chapter 9 Work and Kinetic Energy I am sick and tired of your forces!!! Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsi IN THIS CHAPTER, you will learn how to solve problems

More information

Potential Energy & Conservation of Energy

Potential Energy & Conservation of Energy PHYS 101 Previous Exam Problems CHAPTER 8 Potential Energy & Conservation of Energy Potential energy Conservation of energy conservative forces Conservation of energy friction Conservation of energy external

More information

PHYSICS 231 INTRODUCTORY PHYSICS I

PHYSICS 231 INTRODUCTORY PHYSICS I PHYSICS 231 INTRODUCTORY PHYSICS I Lecture 6 Last Lecture: Gravity Normal forces Strings, ropes and Pulleys Today: Friction Work and Kinetic Energy Potential Energy Conservation of Energy Frictional Forces

More information

Slide 2 / 76. Slide 1 / 76. Slide 3 / 76. Slide 4 / 76. Slide 6 / 76. Slide 5 / 76. Work & Energy Multiple Choice Problems A 1,800 B 5,000 E 300,000

Slide 2 / 76. Slide 1 / 76. Slide 3 / 76. Slide 4 / 76. Slide 6 / 76. Slide 5 / 76. Work & Energy Multiple Choice Problems A 1,800 B 5,000 E 300,000 Slide 1 / 76 Slide 2 / 76 1 driver in a 2000 kg Porsche wishes to pass a slow moving school bus on a 4 lane road. What is the average power in watts required to accelerate the sports car from 30 m/s to

More information

A. B. C. D. E. v x. ΣF x

A. B. C. D. E. v x. ΣF x Q4.3 The graph to the right shows the velocity of an object as a function of time. Which of the graphs below best shows the net force versus time for this object? 0 v x t ΣF x ΣF x ΣF x ΣF x ΣF x 0 t 0

More information

Potential Energy. Serway 7.6, 7.7;

Potential Energy. Serway 7.6, 7.7; Potential Energy Conservative and non-conservative forces Gravitational and elastic potential energy Mechanical Energy Serway 7.6, 7.7; 8.1 8.2 Practice problems: Serway chapter 7, problems 41, 43 chapter

More information

Homework #5. Ph 231 Introductory Physics, Sp-03 Page 1 of 4

Homework #5. Ph 231 Introductory Physics, Sp-03 Page 1 of 4 Homework #. Ph Introductory Physics, Sp-0 Page of -A. A 7 kg block moves in a straight line under the influence of a force that varies with position as shown in the figure at the right. If the force is

More information

CHAPTER 5. Chapter 5, Energy

CHAPTER 5. Chapter 5, Energy CHAPTER 5 2. A very light cart holding a 300-N box is moved at constant velocity across a 15-m level surface. What is the net work done in the process? a. zero b. 1/20 J c. 20 J d. 2 000 J 4. An rock is

More information

UNIVERSITY OF SASKATCHEWAN Department of Physics and Engineering Physics

UNIVERSITY OF SASKATCHEWAN Department of Physics and Engineering Physics UNIVERSITY OF SASKATCHEWAN Department of Physics and Engineering Physics Physics 111.6 MIDTERM TEST #2 November 16, 2000 Time: 90 minutes NAME: STUDENT NO.: (Last) Please Print (Given) LECTURE SECTION

More information

Phys101 Lectures 9 and 10 Conservation of Mechanical Energy

Phys101 Lectures 9 and 10 Conservation of Mechanical Energy Phys101 Lectures 9 and 10 Conservation of Mechanical Energy Key points: Conservative and Nonconservative Forces Potential Energy Generalized work-energy principle Mechanical Energy and Its Conservation

More information

Power: Sources of Energy

Power: Sources of Energy Chapter 5 Energy Power: Sources of Energy Tidal Power SF Bay Tidal Power Project Main Ideas (Encyclopedia of Physics) Energy is an abstract quantity that an object is said to possess. It is not something

More information

The diagram below shows a block on a horizontal frictionless surface. A 100.-newton force acts on the block at an angle of 30. above the horizontal.

The diagram below shows a block on a horizontal frictionless surface. A 100.-newton force acts on the block at an angle of 30. above the horizontal. Name: 1) 2) 3) Two students are pushing a car. What should be the angle of each student's arms with respect to the flat ground to maximize the horizontal component of the force? A) 90 B) 0 C) 30 D) 45

More information

Lesson 5. Luis Anchordoqui. Physics 168. Tuesday, September 26, 17

Lesson 5. Luis Anchordoqui. Physics 168. Tuesday, September 26, 17 Lesson 5 Physics 168 1 C. B.-Champagne Luis Anchordoqui 2 2 Work Done by a Constant Force distance moved times component of force in direction of displacement W = Fd cos 3 Work Done by a Constant Force

More information

Dynamics: Forces. Lecture 7. Chapter 5. Course website:

Dynamics: Forces. Lecture 7. Chapter 5. Course website: Lecture 7 Chapter 5 Dynamics: Forces Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsi Today we are going to discuss: Chapter 5: Some leftovers from rotational motion Ch.4 Force,

More information

Dynamics: Forces and Newton s Laws of Motion

Dynamics: Forces and Newton s Laws of Motion Lecture 7 Chapter 5 Physics I Dynamics: Forces and Newton s Laws of Motion Course website: http://faculty.uml.edu/andriy_danylov/teaching/physicsi Today we are going to discuss: Chapter 5: Force, Mass:

More information

Chapter 4 Newton s Laws

Chapter 4 Newton s Laws Chapter 4 Newton s Laws Isaac Newton 1642-1727 Some inventions and discoveries: 3 laws of motion Universal law of gravity Calculus Ideas on: Sound Light Thermodynamics Reflecting telescope In this chapter,

More information

Unit 08 Work and Kinetic Energy. Stuff you asked about:

Unit 08 Work and Kinetic Energy. Stuff you asked about: Unit 08 Work and Kinetic Energy Today s Concepts: Work & Kinetic Energy Work in a non-constant direction Work by springs Mechanics Lecture 7, Slide 1 Stuff you asked about: Can we go over the falling,

More information

Slide 1 / A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? 10 km 22.5 km 25 km 45 km 50 km

Slide 1 / A train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? 10 km 22.5 km 25 km 45 km 50 km Slide 1 / 96 1 train moves at a constant velocity of 90 km/h. How far will it move in 0.25 h? 10 km 22.5 km 25 km 45 km 50 km Slide 2 / 96 2 bicyclist moves at a constant speed of 6 m/s. How long it will

More information

LAHS Physics Semester 1 Final Practice Multiple Choice

LAHS Physics Semester 1 Final Practice Multiple Choice LAHS Physics Semester 1 Final Practice Multiple Choice The following Multiple Choice problems are practice MC for the final. Some or none of these problems may appear on the real exam. Answers are provided

More information