1. What three dimensions are used to derive most measurements in physics?

Size: px

Start display at page:

Download "1. What three dimensions are used to derive most measurements in physics?"

Jesse Joseph
6 years ago
Views:

1 Physics Semester 1 Exam Review Unit 1: Measurement What is the SI unit for length, mass, and time? When are zeros significant figures? When are zeros not significant figures? When are calculations rounded-off based on least precision? When are calculations rounded-off based on significant figures? What is the difference between precision and accuracy? 1. What three dimensions are used to derive most measurements in physics? Unit 2: Motion How are scalars and vectors different? What quantities are scalars? What quantities are vectors? What is the sum of two vectors? What is the final velocity for an accelerating object as a function of time? What is the displacement for an accelerating object? What is the final velocity of an object independent of time? Interpret a graph of displacement, velocity, or acceleration as a function of time. How high does projectile go? How far does a projectile go? How much time does a projectile stay in the air? What is the velocity of an object from the viewpoint of another moving object? Key vocabulary: displacement velocity acceleration 1. A boat goes 8 m/s due north against a current of 3 m/s. What is the resultant velocity of the boat? 2. A bird navigates 1.8 m west and 7.0 m north. Sketch a vector diagram of this motion and determine the magnitude and direction of the bird s displacement with respect to its original position. 3. Multiplying or dividing vectors by scalars results in what? 1

2 4. Identify each of the following as vectors or scalars: a. mass of an object b. volume of a liquid c. number of petals on a rose d. wind velocity e. a cheetah s maximum speed f. time g. force h. momentum 5. A plane flies from point A to point B. B is 1207 km west and 957 km south of A. Sketch a picture of this situation. What is the total displacement (magnitude and direction) of the plane? 6. Vector A and resultant vector R are shown below. What does vector B have to look like so that it could be added to vector A and produce resultant vector R? (Sketch your answer.) A R 7. Which pair of vectors will produce the resultant with the biggest magnitude? A B C D 8. Shown are vectors A, B, and C. Sketch A + B. A B C 9. Use the diagram at right to answer the following questions: a. Which displacement vectors have horizontal components? b. Which displacement vectors have vertical components? c. Which have components lying along the y-axis and are pointed in the y-direction? d. Which have vertical components that are equal? 10. A sailboat goes 1.65 km/h. How far has the boat traveled in 0.70 h? 11. A plane accelerates at 20 m/s 2 from rest and lifts off the runway after 7 s. How far did it travel down the runway before lifting off? 2

3 12. Answer the following questions about the graph to the right: a. What type of graph is shown? b. What information would we get from finding the slope of the line? c. What information would we get from finding the area under the curve? d. What is the acceleration at point A? e. What is acceleration at point B? 13. Acceleration can be a change in or a change in. 14. A runner starts from rest and after 3.0 s is running at 4 m/s. What is the runner s average acceleration? 15. A ball is released from rest and falls freely 8.0 m to the ground. What is the speed before impact? 16. Graph ABCD represents the motion of an object. Velocity is plotted against time. For each segment in the graph, find the distance covered and the acceleration. Distance Acceleration AB BC CD DE A rock is thrown straight upward with an initial velocity of 12.2 m/s from a location where the acceleration due to gravity is 9.81 m/s 2. How high up does it go? 3

4 18. Answer the questions that follow using the graph at the right. a. What is the speed of the object at the 5.0 second point? b. How far did the vehicle travel in the time interval shown? c. What is the acceleration of the vehicle between t = 0 s to 10s? d. Describe the velocity and acceleration of the vehicle. Velocity is Acceleration is 19. If a freely falling object were dropped from rest and equipped with a speedometer, approximately what would the reading say after a. 1 s? b. 2 s? c. 3 s? d. 4 s? 20. A Corvette accelerates at a constant rate from rest to a speed of 32.4 m/s in 7.00 s. What is the displacement of the Corvette in this time interval? 21. Answer the following questions about graphical analysis of motion: a. How do you find the speed/velocity from a postion/displacement-time graph? b. How do you find acceleration from a speed/velocity-time graph? c. How do you find velocity from an acceleration-time graph? d. How do you find displacement from a velocity-time graph? 22. The graph below shows the motion of a cat. During which time interval does the cat have the greatest positive velocity? How do you know? 23. A rock is thrown horizontally with an initial velocity of 23.0 meters per second from the top of a tower 72 meters high. (g = 9.81 m/s 2 and neglect air resistance) a. What is the initial vertical velocity of the rock? b. What is the initial horizontal velocity of the rock? c. How long does it take the rock to reach the ground? d. What is the horizontal velocity of the rock just before it reaches the ground? e. What is the vertical velocity of the rock just before it reaches the ground? f. What is the velocity of the rock just before it reaches the ground? 4

5 24. A velocity vector with a magnitude of 25.0 m/s at a heading of 60.0 to the +x-axis a. has what x-component? b. has what y-component? 25. A toy is tossed from the edge of a table. Its path is shown; air resistance is ignored. Use the picture below to answer the following questions. a. At what position is the toy s speed the greatest? b. At which position is the toy s speed about equal to the speed at which it was first released? c. At which position is it s vertical speed the least? d. At which position is it s horizontal speed the greatest? Unit 3: Forces How do field forces differ from contact forces? What is the SI unit for force? What is Newton s Second Law (in words)? How is net force computed? How is weight computed? What is Newton s First Law? What is the net force and what is the acceleration during equilibrium? What forces are shown in a free-body diagram? What is Newton s Third Law? What is an action-reaction pair? How are static friction and kinetic friction different? What factors affect friction? Key vocabulary: force net force normal force friction 1. State each of Newton s laws of motion and give an example of each. First Law Second Law Third Law 5

6 2. Identify the action reaction pairs in the following situations: a. A volleyball player spikes the ball b. A hammer hits a nail into a wall c. A car smashes into mailbox 3. If an object has more mass it has more. 4. Cart 1 has a mass of 1 kg. Cart 2 has a mass of 2 kg. They are pushed apart by a spring. The spring exerts 2 N of force onto cart 1. How much force is exerted onto cart 2? 5. A small plane has a mass of 3000 kg and accelerates at 10 m/s 2 down the runway. What is the magnitude of the force acting on the plane? 6. What happens when the same force is applied to two objects of different masses? 7. A 3.0 kg block is on a frictionless horizontal surface. F 1 = 10.0 N and pulls to the left. F 2 = 13.0 N and pulls to the right. What is the acceleration of the block? 8. If a non-zero net force is acting on an object, what is happening to the object? 9. How can you get a moving object to change direction? 10. Answer the questions that follow about the picture shown below at right. a. What is the gravitational force acting on the car? b. What is the normal force acting on the car? c. What is the frictional force acting on the car? d. What is the applied force acting on the car? e. What is the net horizontal force acting on the car? f. What is the net vertical force acting on the car? 11. A cart with a weight of N is accelerated across a level surface at 0.75 m/s 2. What net force acts on the wagon? (g = 9.81 m/s 2 ) 12. My dog has a mass of 10 kg when she stands with all four paws on the scale. What will her mass be if she stands on only her two hind legs? 13. Driving along one day, a giant beetle splatters against my windshield. Which is greater, the force acting on the windshield or the force acting on the beetle? 14. A force of 35 N is applied horizontally to a 4.0 kg crate initially at rest on a horizontal frictionless surface. If the crate displaces 15 m, what would be its final velocity? 6

7 15. A mass of exactly kg is sitting on a flat wooden board. A spring scale is attached to the mass. A reading of N is needed to just start to drag the mass over the board. a. What is the value of the force of static friction? b. What is the value of the normal force on the mass? c. What is the value of the coefficient of static friction? 16. What can affect the coefficient of friction between two surfaces? What absolutely does not affect the coefficient of friction? Unit 4: Gravitation What is Kepler s first law of motion? What is Kepler s second law of motion? As a planet orbits the sun, what velocity changes occur? What is Kepler s third law of motion? How does the orbital period of planet far from the sun compare with a planet nearer the sun? What is Newton s Law of Universal Gravitation (in words)? How is the gravitational force between two objects computed? 1. In the drawing below, two small masses are separated by 20.0 cm. They attract each other with a force of 10.0 N. M cm M2 a. When they are 10.0 cm apart, these masses will attract each other with what force? b. When they are 5.0 cm apart, these masses will attract each other with what force? c. When they are 40.0 cm apart, these masses will attract each other with what force? 2. A 60.3 kg student sits 2.34 m away from a 72.7 kg student. What is the magnitude of the gravitational force between the two students? (G = x Nm 2 /kg 2 ) 3. A 60.3 kg student sits 2.34 m away from a 72.7 kg student. What is the magnitude of the gravitational force between the two students? (G = x kg) Unit 5: Rotational Motion How is torque computed? Apply rotational equilibrium to determine how much torque is needed. Key vocabulary: lever arm distance torque uniform circular motion centripetal acceleration centripetal force 7

8 1. 1. The torque required to loosen a nut on a wheel has a magnitude of 60 Nm and the force exerted by the technician is 240 N. How far from the nut must the technician apply the force? 2. A rubber stopper on a string swings in a circular path with a radius of 0.5 m. The tangential speed of the stopper is 2.3 m/s. The mass of the stopper is 0.20 kg. What the stopper s centripetal acceleration? 3. A person on a bike with a combined mass of 105 kg turns in a circular drive with a radius of 20 m. If her speed is 12 m/s, what is the centripetal force acting on the bike and rider? 4. The diagram below shows the top view of a student on the Gravitron. The ride spins the student counter clockwise in a horizontal circle at a constant speed. The floor is lowered and the student remains against the wall without falling to the floor. Unit 6: Momentum a. Draw the vector that represents the centripetal acceleration of the student at the point show. b. If the student s speed is 10 m/s what is her centripetal acceleration? c. If her mass is 66.0 kg, what is the centripetal force acting on her? Student 3.0 m How is impulse computed? How is linear momentum computed? How are impulse and momentum related? How are beginning and ending linear momentum related? How is Angular momentum computed? How are beginning and ending angular momentum related? Key vocabulary terms: impulse momentum 1. An open train car rolls along a track while it is being filled with sand. There is negligible friction. As a result of the accumulating sand, what happens to the speed of the train car? (Assume negligible friction and the cart is just rolling along, not receiving any additional force to regulate its speed.) 2. A hockey player initially skating at a velocity of 5 m/s speeds up to 8 m/s. What happens to the momentum of the hockey player? 3. A 70 kg student running down the halls bumped into a 90 kg student who was running down the hall towards her. What happens to the magnitude of the momentum of the 90 kg person? 8

9 4. Change in momentum is equal to what? What is this called? 5. If a non-zero net force is applied to an object, will the momentum of the object change? What else affects how much the momentum will change? 6. A 70 kg hockey player exerts a 15N force on a 62 kg hockey player for 0.3 s. What is the magnitude of the impulse applied to the 60 kg hockey player? 7. Impulse is equal to the change in an object s? 8. A racquetball moving at 7 m/s hits the wall of the court and rebounds to the hitter at 7 m/s. What happened to the size of the momentum of the racquetball? 9. A 50 Ns impulse is exerted on a 0.25 kg mass for 0.30 s by a 5.0 kg object. What is the change in momentum of the 0.25 kg object? Unit 7: Work, Energy and Power How is work computed? How is power computed? How is kinetic energy computed? How is gravitational potential energy computed? What are the SI units for work, power and energy. What does the graph of potential energy plus kinetic energy generally look like? What is the Work-Energy Theorem? What is the Law of Conservation of Energy? What is the difference between elastic and inelastic collisions? Key vocabulary: work power kinetic energy elastic potential energy gravitational potential energy mechanical energy 1. The sum of the potential energies and the kinetic energy is called what? 2. What two things must occur in order for work to be done? 3. How are work and kinetic energy related? 4. How are work and potential energy related? (Think of an object that has been lifted to some elevation off the ground.) 9

10 5. A person mowing a lawn with a push mower exerts a force of 100 N at an angle of 30.0 above the horizontal. Sketch a picture of this situation. How much work does he do when he moves 27.0 meters, at a constant velocity? 6. A 30.0 kg child on roller skates, initially at rest, rolls 4.0 m down an incline at an angle of 25.0 with the horizontal. If there is no friction between the incline and the skates, what is the kinetic energy of the child at the bottom of the incline? (g = 9.81 m/s 2 ) [Hint: Remember that this is a work/energy question!] 7. The diagram below shows points A, B, C, and D at or near the Earth s surface. As a mass is moved from A to B 150 joules of work are done against gravity. a. What is the amount of work done against gravity as an identical mass is moved from A to C? b. What is the amount of work done against gravity as an identical mass is moved from A to D? 8. When an object s speed doubles, what happens to its kinetic energy? When speed triples? 9. A 4.0 kg mass is dropped from a height of 15.0 m. What will its kinetic energy be just before it hits the ground? (Disregard air resistance, g = 9.81 m/s 2 ) 10. A ball of mass kg rolls off a tabletop at a speed of 3.0 m/s. The table is 1.14 m high. Assume the potential energy at the floor is zero. Disregard any rotational energy. a. What is the total energy of the ball as it rolls on the table top? b. While the ball is in the air, after it leaves the table, what happens to the relationship between its kinetic and potential energies? c. What is the value of the kinetic energy of the ball when it strikes the floor? B 10.0 A 20.0 m C D 10.0 Unit 8: Thermal Physics What is the most important indicator of thermal energy? At the temperature of a substance increases, what happens to the average kinetic energy of its molecules? As the temperature of a substance increases, what happens to the average spacing of its molecules? (In general, how is size related to temperature?) What happens to water as it cools from 4 O C to 0 O C? How does water s behavior from 4 O C to 0 O C benefit plants and animals? How much thermal energy (heat) is needed to change the temperature of a given mass by a given amount? Is Thermal Energy conserved in a particular situation? What must happen for a substance to melt or vaporize? to condense or freeze? What is the difference between a solid, a liquid, and a gas? 10

11 What is the First Law of Thermodynamics? What is the Second Law of Thermodynamics? In all natural processes, what happens to entropy? What is the Ideal Gas Law? Key vocabulary: heat specific heat plasma conduction convection radiation entropy 1. Heat flow will occur between two objects in thermal contact under what condition? 2. What does the first law of thermodynamics state? 3. In all natural processes, the entropy of the universe will do what? 4. Explain why, when you jump into a pool just after the first strong cold front of winter, the water is still very warm. General For each of the following, list the symbol and possible units. Symbol Units Time Distance Displacement Speed Velocity Acceleration Mass Force Friction Weight Work Energy Power Momentum Impulse Centripetal force Centripetal acceleration Torque Heat Specific heat Latent heat 11

Page 1. Name: Section This assignment is due at the first class in 2019 Part I Show all work!

Page 1. Name: Section This assignment is due at the first class in 2019 Part I Show all work! Name: Section This assignment is due at the first class in 2019 Part I Show all work! 7164-1 - Page 1 1) A car travels at constant speed around a section of horizontal, circular track. On the diagram provided