energy, length, and time mass, energy, and time mass, length and time

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1 1 All units in mechanics can be derived from what units? mass, length, and energy energy, length, and time mass, energy, and time mass, length and time 2 What is the fundamental SI units for time? minute day second hour 3 What trig function would you use to compute the angle of a right triangle if you know the magnitudes of the hypotenuse and the side opposite the angle? sine cosine tangent resultant 4 Which formula is dimensionally consistent with an expression yielding a value for time? (v has units m/s and x has units of m) x/v x/v 2 t/ x (1/v 2 ) t 5 Which of the following prefixes does NOT represent of fractional part of a whole unit such as a meter, gram, liter etc.? E nano micro kilo milli deci 6 What must you do to convert a quantity from km/h to m/s? multiply by 1000 and divide by 60 multiply by 1000 and divide by 3600 multiply by 60 and divide by 1000 multiply by 3600 and divide by All units we have used in physics this semeste can be derived from what quantities? E mass, length, and energy force, length, and time mass, acceleration, and velocity mass, length and time momentum, length and time 8 Which is a derived unit? meter second kilogram Newton 9 Which measurement of an average classroom door is closest to 1 meter? thickness width height surface area 10 Which quantity and unit are correctly paired? velocity - m/s 2 acceleration - m 2 /s 2 energy - kg.m 2 /s 2 work - kg/m

2 11 Which graph below shows a linear relationship? 12 What does the slope of the tangent on a position-time graph equal? average speed constant speed average velocity instantaneous velocity 13 What does the area under the curve on a velocity-time graph equal? rise divided by the run displacement from the original position to its position at time t relative velocity instantaneous velocity 14 The graph shows the velocity of each of two bodies as a function of time. Which quantities must be the same for both of the bodies? distance covered the average velocity inertial mass acting on the bodies acceleration 15 An object moves along the x axis as shown in the diagram. At which point or points is the object at rest? a and e b, d, e c only e only

3 16 Which graph of v versus t best describes the motion of a particle whose velocity is constant and negative? E 17 In which graph is the particle the farthest from the origin at t = 5 s E 18 The diagram below represents the relationship between velocity and time of travel for four cars, A, B, C, and D, in straight-line motion. Which car has the greatest acceleration during the time interval 10. seconds to 15 seconds 19 The displacement-time graph below represents the motion of a cart initially moving forward along a straight line. During which interval is the cart moving forward at constant speed? AB BC CD DE

4 20 The graph below represents the relationship between the forces applied to an object and the corresponding accelerations produced. What is the mass of the object? 1.0 kg 2.0 kg 0.50 kg 1.5 kg 21 Which one of the following is the correct force vector diagram showing z as the resultant of x and y? 22 What must you do to add vectors graphically? Draw the vectors head to tail in order. The resultant (sum ) is drawn from the tail of the first to the head of the last. Draw the vectors tail to tail. The resultant is drawn from the head of the first to the head of the last. Draw the vectors heat to tail in any order. The resultant is drawn from the head of the first to the tail ofthe last. Draw the vectors head to tail in any order. The resultant is drawn from the tail of the first to the head of the last. 23 Use the vector diagram below to determine the equilibrant of forces x and y.

5 24 Which vector in the figure could represent the vector A - B? E Identify the following quantities in order as scalar or vector: the speed of a snail, the time it takes to run a mile, the free-fall acceleration. E vector, scalar, scalar scalar, scalar, vector vector, scalar, vector scalar, vector, vector vector, vector, vector 26 The angle between vectors A and B is 30 0, and their sum is C. Draw a vector diagram that correctly describes the vectors A, B, and C? E 27 Vectors A and B have the components shown in the table below. What is the magnitude of the vector A - B? E 6.3 units 10.0 units 2.8 units 8.2 units 16 units 28 Which two terms represent a vector quantity and the scalar quantity of the vector's magnitude, respectively? acceleration and velocity weight and force speed and time displacement and distance 29 Which is a vector quantity? distance speed power force

6 30 What is the vector in the figure that could represent the vector A + B? E The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which drawing shows constant velocity. 32 The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which drawing shows the object speeding up.

7 33 The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which drawing shows the object slowing down. A, B, C A, D, F B, C C 34 The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which object has a negative acceleration, 35 The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which drawing shows negative acceleration? A and C D and F B and E None of the Examples

8 36 The following drawings indicate the motion of a ball subject to one or more forces on various surfaces from left to right. Each circle represents the position of the ball at succeeding instants of time. Each time interval between successive positions is equal. Which drawing shows a positive acceleration. A and F D and E B and E D and F 37 The following objects are sitting, falling, or rolling as indicated in the different situations below. Each has an acceleration in some direction or another. Which object has the greatest velocity Object dropped from the top of a building. Object rolling from rest down an inclined plane Object rolling up an inclined plane after being given an initial velocity of 4 m/s. Object sitting on a table top motionless 38 The eight figures below depict eight model rockets that have just had their engines turned off. All of the rockets are aimed straight up, but their speeds differ. All of the rockets are the same size and shape, but they carry different loads, so their masses differ. The specific mass and speed for each rocket is given in each figure. (In this situation, we are going to ignore any effect air resistance may have on the rockets.) At the instant when the engines are turned off, the rockets are all at the same height, Which rockets will go the highest B and H B and F B, E and H A and D

9 39 The eight figures below depict eight model rockets that have just had their engines turned off. All of the rockets are aimed straight up, but their speeds differ. All of the rockets are the same size and shape, but they carry different loads, so their masses differ. The specific mass and speed for each rocket is given in each figure. (In this situation, we are going to ignore any effect air resistance may have on the rockets.) At the instant when the engines are turned off, the rockets are all at the same height, Which rockets will have the greatest net force. A and D B and F C, F, G They all have the same force because the observed acceleration is the same 40 The eight figures below show arrows that have been shot into the air. All of the arrows were shot straight up and are the same size and shape. But the arrows are made of different materials so they have different masses, and they have different speeds as they leave the bows. The values for each arrow are given in the figures. (We assume for this situation that the effect of air resistance can be neglected.) All start from same height. Which arrows reach the greatest height. Arrow A Arrows A and F Arrow C None they all rise to the same height because of the acceleration of gravity.

10 41 The eight figures below show arrows that have been shot into the air. All of the arrows were shot straight up and are the same size and shape. But the arrows are made of different materials so they have different masses, and they have different speeds as they leave the bows. The values for each arrow are given in the figures. (We assume for this situation that the effect of air resistance can be neglected.) All start from same height. Which arrows have the same observed acceleration. Arrows A and F Arrows B and D Arrows E and H They all have the same observed acceleration 42 In the position vs. time graphs below, all the times are in seconds (s), and all the positions are in meters (m). Which graphs show the greatest displacement A C E F 43 In the position vs. time graphs below, all the times are in seconds (s), and all the positions are in meters (m). Which graph indicates the greatest average speed, where the average speed is calculated from the beginning to the end of motion.

11 44 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the greatest displacement during the first three second? Drawing A Drawing B Drawing C Drawing D 45 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the greatest velocity during the first three second? Drawing A Drawing B Drawing C Drawing D 46 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the greatest velocity during the first three second? Drawing B Drawing C Drawing D Drawing E

12 47 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the smallest velocity during the first three second? Drawing C Drawing D Drawing E Drawing F 48 Pictured below are three waterfalls all of which have the same amount of water flowing over them. The waterfalls differ in the speed of the water as it goes over the edge. The specific values of the speeds are given in the figures. Which water fall hits the ground first? They all hit at the same time. 49 Pictured below are three waterfalls all of which have the same amount of water flowing over them. The waterfalls differ in the speed of the water as it goes over the edge. The specific values of the speeds are given in the figures. Which water fall hits the ground furthest from the cliff? They all hit at the same distance from the water fall

13 50 Pictured below are three waterfalls all of which have the same amount of water flowing over them. The waterfalls differ in the speed of the water as it goes over the edge. The specific values of the speeds are given in the figures. Which water fall hits the ground furthest from the cliff? 51 Pictured below are arrows that have been shot horizontally, i.e., straight out, by archers on platforms. All of the arrows are identical, but they have been shot at different speeds from platforms of varying height. Specific values for the speeds and of varying heights are given in the figures. All of the arrows miss the targets and hit the ground. Which arrow will take the longest time to hit the ground They all hit the ground at the same time. 52 Pictured below are arrows that have been shot horizontally, i.e., straight out, by archers on platforms. All of the arrows are identical, but they have been shot at different speeds from platforms of varying height. Specific values for the speeds and of varying heights are given in the figures. All of the arrows miss the targets and hit the ground. Which arrow will take the shortest time to hit the ground

14 53 Shown below are rocks that have been thrown into the air. The rocks all have the same shape, but they have different masses. The rocks are all thrown at the same angle, but at different speeds. The masses of the rocks and their speeds, when released, are given in the figures. (We assume for this situation that the effect of air resistance can be ignored.) All start from the same height. Which rock reaches the greatest height 54 Shown below are diagrams of situations where carts, initially moving along a horizontal surface, run up onto short inclines. The carts go up off the inclines. All of the inclines have the same angle, and they are very smooth, so there is essentially no friction. The masses of the carts and their speeds when they reach the inclines are given in the figures. Which car goes up the ramp to the highest point. 55 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the greatest displacement during the first three second? Drawing C Drawing D Drawing E Drawing F

15 56 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the greatest displacement during the first 4 second? Drawing B Drawing D Drawing E Drawing F 57 Flash strobe photographs were taken every second of a set of spheres moving from left to right. The diagram below shows the location of each sphere when each photograph was taken. The total time intervals shown vary among the spheres. All the displacements are in meters. Which drawing shows the smallest displacement during the first three second? Drawing B Drawing C Drawing D Drawing E 58 A man walks 40 meters north, then 70 meters east and then 40 meters south. What is his displacement from the starting point? 150 meters east 150 meters west 70 meters east 70 meters west 59 An object is accelerated from rest at the rate of 3.0 m/s 2. What is its velocity After it has traveled 13.5 m? 3.0 m/s 6.0 m/s 9.0 m/s 12.0dm/s 60 A truck traveled 60 miles in one (1) hour. Which statement about the truck is always true? The average speed is 60 mi/hr. The speed was a constant 60 mi/hr. The instantaneous acceleration was zero. The truck did not stop during the trip.

16 61 When velocity is positive and acceleration is negative, what happens to the object's motion? The object slows down. The object speeds up. Nothing happens to the object. The object remains at rest. 62 Which of the following is the expression for acceleration? E a = t/ v a = v/ t a = t x v a = (v i -v f ) / (t i - t f ) a = (v i -v f ) x (t i - t f ) 63 A toy car is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.0 m/s 2. What is the final velocity after 6.0 s? E 10.0 m/s 12 m/s 16 m/s 17 m/s 34 m/s 64 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 interval? 2.5 m/s 5.0 m/s 6.5 m/s 7.0 m/s 65 An airplane originally at rest on a runway accelerates uniformly at 6.0 m/s 2 for 12 seconds. During this 12 second interval, the airplane travels a distance of approximately 72 m 220 m 430 m 860 m 66 If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the path length you have traveled? 6.5 km 2.5 km 10.5 km 0 km 67 If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the magnitude of your displacement? 6.5 km 2.5 km 10.5 km 9.0 km

17 68 What is the velocity of an object if it falls freely from rest for 4.0 seconds? 20 m/s downward 40 m/s downward 60 m/s downward 80 m/s downward 69 A bullet shot horizontally from a gun: Strikes the ground much later than one dropped vertically from the same point at the smae instant. Is brought to rest by air resistance alone. Strikes the ground at approximately the same time as one dropped vertically from the same point at the same instant. Strikes the ground much sooner than one dropped from the same point at the same instant. 70 A stone is thrown horizontally and follows the path XYZ shown. The direction of the resultant velocity of the stone at point Y is: E 71 For an object moving along a trajectory, what happens to the vertical acceleration as the position changes? E increases decreases is constant decreases and then increases increases and then decreases 72 In projectile motion, the rising and falling times of the object are equal if the launching position is the landing position. above below at the same height as none of these choices are correct 73 What is the value for the acceleration of objects in free fall? E m/s m/s m/s m/s A 4.0 kilogram rock and a 10 kilogram stone fall freely from rest from a height of 1.00 meters. What is the ratio of the rock s speed to the stone s speed after both objects fall for two seconds? 1:1 1:2 2:1 4:1

18 75 A ball is thrown horizontally with an initial velocity of 20.0 meters per second from the top of a tower 60.0 meters high. What is the initial vertical velocity of the ball? 0 m/s 9.81 m/s 20.0 m/s 60.0 m/s 76 A ball is thrown horizontally with an initial velocity of 20.0 meters per second from the top of a tower 60.0 meters high. What is the approximate total time required for the ball to reach the ground? [Neglect air resistance.] 1.22 s 2.04 s 3.00 s 3.50 s 77 A ball is thrown horizontally with an initial velocity of 20.0 meters per second from the top of a tower 60.0 meters high. What is the horizontal velocity of the ball just before it reaches the ground? [Neglect air resistance.] m/s 20.0 m/s 34.3 m/s 68.6 m/s

19 78 A particle moves at constant speed in a circular path. The instantaneous velocity and instantaneous acceleration vectors are: both tangent to the circular path. both perpendicular to the circular path. perpendicular to each other. opposite to each other. 79 A 2 kg mass is swung in a horizontal circle with a radius of 1 meter. If it takes 2 seconds to make 1 revolution, find the force on the string? 2.0 kg 79.0 N 39.5 N 19.7 N 80 An object is moving in circular motion. How far does it travel in one period? E r 4πr 2 2πr v 2 /r 4π 2 r/t 2 81 What is an object s acceleration when it moves in a circle with a constant speed? E constantly increasing in magniture and direction constant in direction but changing in magnitue zero. constant in magnitude but changing direction constant in magnitude and direction. 82 A 1.00 x 10 3 kilogram car is driven clockwise around a flat circular track of radius 25.0 meters. The speed of the car is a constant 5.00 meters per second. What minimum friction force must exist between the tires and the road to prevent the car from skidding as it rounds the curve? 1.25 x 10 5 N 9.80 x 10 4 N 5.00 x 10 3 N 1.00 x 10 3 N

20 83 A 1.00 x 10 3 kilogram car is driven clockwise around a flat circular track of radius 25.0 meters. The speed of the car is a constant 5.00 meters per second. If the circular track were to suddenly become frictionless at the instant shown in the diagram, the car s direction of travel would be toward E toward N toward W a clockwise spiral 84 Base your answers on the information and diagram below. A 1.00 x 10 3 kilogram car is driven clockwise around a flat circular track of radius 25.0 meters. The speed of the car is a constant 5.00 meters per second. At the instant shown in the diagram, the car s centripetal acceleration is directed toward E toward W toward N clockwise 85 Base your answers on the information and diagram below. A 1.00 x 10 3 kilogram car is driven clockwise around a flat circular track of radius 25.0 meters. The speed of the car is a constant 5.00 meters per second. Which factor, when doubled, would produce the greatest change in the centripetal force acting on the car? mass of the car radius of the track velocity of the car weight of the car

21 86 A heavy ball is attached to a string and swung in a circular path in a horizontal plane as illustrated in the diagram below. At the point indicated in the diagram, the string suddenly breaks at the ball. If these events were observed from directly above, indicate the path of the ball after the string breaks. E Path A Path B Path C Path D Path E 87 The accompanying diagram depicts a semicircular channel that has been securely attached, in a horizontal plane, to a table top. A ball enters the channel at "1" and exits at "2". Which of the path representation would most nearly correspond to the path of the ball as it exits the channel at "2" and rolls across the table top. E Path A Path B Path C Path D Path E 88 If it is known that a net force is acting on an object, then what is the object most likely to be doing? at rest. moving with a constant velocity. being accelerated. losing mass. 89 A 2.0 kilogram mass weighs 10 Newtons on planet X. What is the acceleration due to gravity on planet X? E 0.20 m/s m/s m/s m/s 2 Do not choose this selection 90 The magnitude of the force that a baseball bat exerts on a ball is 50 Newtons. What is the magnitude of the force that the ball exerts on the bat? 5.0 N 1.0 N 50 N 250 N 91 If the sum of all the forces acting on a moving object is zero, the object will slow down and stop change the direction of its motion accelerate uniformly continue moving with constant velocity

22 92 Which of Newton's laws best explains why motorists should buckle-up? the first law the second law the third law the law of gravitation 93 A rocket moves through empty space in a straight line with constant speed. It is far from the gravitational effect of any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is equal to its weight. equal to its mass. dependent on how fast it is moving. zero. 94 You are standing in a moving bus, facing forward, and you suddenly fall forward. What can you conclude about the bus s motion? velocity decreased. velocity increased. speed remained the same, but it's turning to the right. speed remained the same, but it's turning to the left. 95 A net force F accelerates a mass m with an acceleration a. If the same net force is applied to mass 2m, what will be the new acceleration? 4a. 2a. a/2. x a/4. 96 What are action-reaction forces? equal in magnitude and point in the same direction. equal in magnitude but point in opposite directions. unequal in magnitude but point in the same direction. unequal in magnitude and point in opposite directions 97 A child's toy is suspended from the ceiling by means of a string. The Earth pulls downward on the toy with its weight force of 8.0 N. If this is the "action force," what is the "reaction force"? The string pulling upward on the toy with an 8.0-N force. The ceiling pulling upward on the string with an 8.0-N force. The string pulling downward on the ceiling with an 8.0-N force. The toy pulling upward on the Earth with an 8.0- N force. 98 What is the force required to accelerate a mass of kg at 4.00 m/s 2? 40.0 N 10.0 N 4.00 N 2.50 N 99 A man of mass 70 kg stands on platform scales in an elevator. Suppose the scales read 750 N. How is the elevator moving at that time? Moving up at constant speed Moving down at constant speed Moving down at constant acceleration Moving up at constant acceleration

23 100 Two tugboats have parallel tow lines attached to the same barge. The tugboats are pulling in the same direction, both with a force of 9 x 10 3 N. What is the net force in the direction of the tow lines? greater than 1.5 x 10 4 N between 1.0 x 10 4 N and 1.5 x 10 4 N between 5 x 10 3 N and 1.0 x 10 4 N less than 5 x 10 3 N 101 If the force of gravity on a balloon is 3000 N, and the lift force provided by the atmosphere is 3300 N, in which direction is the net force acting? upward downward toward the east There is no net force. 102 A wagon with a weight of N is accelerated across a level surface at 0.5 m/s 2. What net force acts on the wagon? (g = 9.81 m/s 2 ) 9.0 N 15 N 150 N 610 N 103 In which situation is the net force on the object equal to zero? a satellite moving at constant speed around Earth in a circular orbit an automobile braking to a stop a bicycle moving at constant speed on a straight, level road a pitched baseball being hit by a bat 104 The diagram below shows a horizontal 8.0 Newton force applied to a 4.0 kilogram block on a frictionless table. What is the magnitude of the block s acceleration? 0.50 m/s m/s m/s 2 32 m/s An object of mass m is hanging by a string from the ceiling of an elevator. The elevator is moving upward, but slowing down. What is the tension in the string? less than mg exactly mg greater than mg zero 106 A person of weight 480 N stands on a scale in an elevator. What will the scale be reading when the elevator is accelerating downward at 4.00 m/s 2? 196 N 284 N 676 N 480 N

24 107 A large box is being pushed across the floor at a constant speed of 4.0 m/s. What can you conclude about the forces acting on the box? E If the force applied to the box is doubled, the constant speed of the box will increase to 8.0 m/s. The amount of force applied to move the box at a constant speed must be more than its weight. The amount of force applied to move the box at a constant speed must be equal to the amount of frictional forces that resist its motion. The amount of force applied to move the box at an constant speed must be more than the amount of the frictional forces that resist its motion. There is a force being applied to the box to make it move but the external forces such as friction are not "real" forces they just resist motion. 108 When is friction is a disadvantage? walking along a sidewalk automobile brakes roller bearings on freight cars between bike tires and the dirt trail 109 Find the force due to friction between a 20 Newton weight and the surface if the coefficient fo friciton is N 40 N 10 N 20 N 110 A brick slides on a horizontal surface. What will increase the frictional force on it? increasing the mass of the brick decreasing the surface area in contact increasing the surface area in contanct decreasing the mass of the brick 111 Find the force due to friction between a 20 Newton weight and the surface if the coefficient of friciton is 0.2 E 4 N 40 N 10 N 20 N 2 N 112 A wooden block is at rest on a horizontal steel surface. If a 10.0 Newton force applied parallel to the surface is required to set the block in motion, how much force is required to keep the block moving at constant velocity? less than 10.0 N greater than 10.0 N 10.0 N Do not choose this selection 113 The table below lists the coefficients of kinetic friction for four materials sliding over steel. A 10 kilogram block of each of these materials is pulled horizontally across a steel floor at constant velocity. Which block requires the smallest applied force to keep it moving at constant velocity? E aluminum brass copper steel Not a choice

25 114 A 50 newton horizontal force is needed to keep an object weighing 500. Newtons moving at a constant velocity of 2.0 meters per second across a horizontal surface. The magnitude of the frictional force acting on the object is E 500. N 450. N 50. N 0 N This is not a choice 115 A different force is applied to each of four 1 kilogram blocks to slide them across a uniform steel surface at constant speed as shown below. In which diagram is the coefficient of friction between the block and steel smallest? 116 The diagram below shows a granite block being slid at constant speed across a horizontal concrete floor by a force parallel to the floor. Which pair of quantities could be used to determine the coefficient of friction for the granite on the concrete? mass and speed of the block mass and normal force on the block frictional force and speed of the block frictional force and normal force on the block 117 Why is it more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity? the normal force is greater when the carton is at rest. µ s < µ k. initially, the normal force is not perpendicular to the applied force. µ k < µ s. 118 A 40kg boy is playing with his 20 kg sister who is sitting in a box on the floor. Starting from rest, he pushes the box with a constant horizontal force of 150 N for 2 m and then jumps into the box, which stops after sliding 3 m more. What is the direction of the velocity as he slows down? E

26 119 A Rock is falling. There is no air friction. Show the forces acting on the rock E 120 A rock is tied to a post and moving in a circle at constant speed on a frictionless horizontal surface. The motion of the rock shows it coming straight out of the paper. What are the forces on the rock? E 121 A rock is hanging motioless by a string. Identify vector B. H A B G C F E D E Tension Force Gravity Force Normal Force Name not identified. Not a part of a correct free body diagram.

27 122 A rock is hanging by a string connected to a block on an inclined plane. Identify vector F. H A B G C F E D E Normal Force Vertical component of the Gravity Force Force Parallel to the Ramp. Name not identified. Not a part of a correct free body diagram. 123 A rock is bumped up next to a stationary block that is connected to an inclined plane. Identify Vector B. A H B G C F E D E Normal Force Push Force Gravity Component parallel to the ramp. Name not identified. Not a part of a correct free body diagram. 124 A rock is suspended by two strings as shown in the picture below. Identify the Net Force E

28 125 A rock is moving to the right and decelerating because of kinetic friction. Identify the Net Force E 126 A rock is rising in a parabolic trajectory. Identify the Net Force E 127 A rock is tied to point A by a string. The rock is moving in a horizontal circle at constant speed. The rock is not resting on a solid surface. Three is no friction. The motion of the rock shows it coming straight out of the paper. Identify the Net Force E

29 128 Find the Equilbrant of the two vectors: 400 N at 30 0 North of East and 600 N at 20 0 East of South N N of W N W of N N N of W N S of W 129 Forces of 6 N and 8 N act on a frictionless puck with a mass of 3 kg at an angle of 90 0 with each other.what is the magnitude in Newtons of the net force on the puck? 14 N 14/3 N 10 N 100/3 N 130 When is an object in equilbrium? the vertical component equals the horizontal component of force the net sum of the forces is zero the resultant force is the equilibrant. all of these 131 A 5 Newton force directed east and a 5 Newton force directed north act concurrently on a point. What is the resultant force? 5 N northeast 10. N southwest 7 N northeast 7 N southwest 132 Which pair of forces acting concurrently on an object will produce the resultant of greatest magnitude?

30 133 The diagram below shows a block on a horizontal frictionless surface. A 100 Newton force acts on the block at an angle of 30 0 above the horizontal. What is the magnitude of force F if it establishes equilibrium? 50.0 N 86.6 N 100. N 187 N 134 The diagram below shows a worker using a rope to pull a cart. The worker s pull on the handle of the cart can best be described as a force having magnitude, only direction, only both magnitude and direction neither magnitude nor direction 135 The diagram below shows a force of magnitude F applied to a mass at angle relative to a horizontal frictionless surface. What happens to the horizontal acceleration of the mass As angle is increased? decreases increases remains the same There is not enough information

31 136 Two people, a large man and a boy, are pulling as hard as they can on two ropes attached to a crate as illustrated in the diagram below. Which of the indicated paths (A-E) would most likely correspond to the path of the crate as they pull it along? E Path A Path B Path C Path D Path E 137 The diagram below shows a force of magnitude F applied to a mass at angle relative to a horizontal frictionless surface. What happens to the normal force on the block as the angle is increased? decreases increases remains the same There is not enough information 138 In the diagram below, a box is at rest on an inclined plane. Which vector best represents the direction of the normal force acting on the box?

32 139 The diagram below shows a 10.0 kilogram mass held at rest on a frictionless 30.0 incline by force F. What is the approximate magnitude of force F? 9.81 N 49.1 N 85.0 N 98.1 N 140 The diagram below shows a block sliding down a plane inclined at angle with the horizontal. What will happen to the coefficient of kinetic friction between the bottom surface of the block and the surface of the incline as angle is increased? decrease increase remain the same There is not enough information given in the problem. 141 Two toy cars (16 kg and 2.0 kg) are released simultaneously on a frictionless inclined plane that makes an angle of 30 with the horizontal. Make a statement which best describes their acceleration after being released. The 16-kg car accelerates 8 times faster than the 2.0-kg car. The 2.0-kg car accelerates 8 times faster than the 16-kg car. Both cars accelerate at the same rate. none of the above 142 A 25 kg object is placed on a frictionless inclined plane. The plane is inclined at an angle of 30 with the horizontal. What is the object's acceleration? 4.9 m/s m/s m/s m/s A 10-kg mass slides down a flat hill that makes an angle of 10 with the horizontal. If friction is negligible, what is the net force on the sled? 1.7 N 17 N 97 N 98 N 144 A mass is placed on a smooth inclined plane with an angle of 37 to the horizontal. If the inclined plane is 5.0-m long, how long does it take for the mass to reach the bottom of the inclined plane after it is released from rest? 1.3 s 1.2 s 1.1 s 1.0 s

33 145 An object with a mass of 15 kg slides down a rough 37 inclined plane where the coefficient of kinetic friction is What is the acceleration of the object? 4.3 m/s m/s m/s m/s The diagram below shows a block sliding down a plane inclined plane of known length from rest at angle with the horizontal. What is the formula you can use to calculate the net force on the block? E µma g cos θ µma g sin θ µma g cos θ + μa g sin θ µma g cos θ + A g sin θ µma g cos θ ma g sin θ 147 The diagram below shows a block sitting on a plane inclined at angle with the horizontal. What will happen with the force of friction between the bottom surface of the block and the surface of the incline as the angle increases? decrease increase remain the same There is not enough information given in the problem. 148 Which of the following is true of an object's momentum? it is a scalar quantity. its dimensions are kg-m it can never change in magnitude it is the product of mass and velocity. 149 Which of the following is an impulse? a 200 N force applied for 2 seconds a change in velocity a short burst of energy an unpredicted event 150 A force of 25.0 N acts on a 12.0 kg object for 5.0 seconds. What is the object's change in momentum? 125 kg.m/s 300 kg 2 /m/s 2 60 kg.s 2.1 m/s 2

34 151 A 2550 kg car collides with a 1730 kg trailer which is at rest. They move off together at 6.2 m/s. Assuming no friction with the ground, find the initial speed of the car. 6.2 m/s 3.1 m/s 9.1 m/s 10.4 m/s 152 Two ice skaters are standing face to face with their palms pressed together. They push away from each other. The 60 kg skatermoves west at 1.5 m/s. What is the velocity of the other skater if his mass is 45 kg? 1.2 m/s, east 2.0 m/s, east 1.2 m/s, west 1.3 m/s, east 153 An impulse occurs between two stationary lab cars (dynamics cars) which are at rest. The total momentum after the impulse is: the product of the impulse times interval over which it acted. zero greater than the original momentum less than the original momentum. 154 A 6.0 kg object A moving at velocity 3.0 m/s collides with an 8.0 kg object at rest. After the collision A moves off in a dirction of 40 degrees to the left of its original direction. B moves off in a direction of 50 degrees to the right of A's original direction. What is object B's speed after the collision? 1.4 m/s 1.7 m/s 13.7 m/s 11.6 m/s 155 A missle in flight explodes. Right after the explosion, what would the total momentum of the flying pieces be? Impossible to know Zero The same as that of the missile before the explosion. More than that of the missile before the explosion. 156 A force of 25.0 N acts on a 12.0 kg object for 5.0 seconds. What is the object's change in momentum? E 125 kg.m/s 300 kg 2 /m/s 2 60 kg.s 2.1 m/s 2 60 kg.m/s 157 A 2550 kg car collides with a 1730 kg trailer which is at rest. They move off together at 6.2 m/s. Assuming no friction with the ground, find the initial speed of the car. 6.2 m/s 3.1 m/s 9.1 m/s 10.4 m/s 158 Two balls of dough collide and stick together. Identify the type of collision. elastic perfectly elastic inelastic perfectly inelastic 159 A clay ball with a mass of 0.35 kg strikes another 0.35 kg clay ball at rest, and the two balls stick together. The final velocity of the balls is 2.1 m/s north. What was the first ball's initial velocity? 4.2 m/s to the north 2.1 m/s to the south 2.1 m/s to the north 4.2 m/s to the south