8. The graph below shows a beetle s movement along a plant stem.

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1 Name: Block: Date: Introductory Physics: Midyear Review 1. Motion and Forces Central Concept: Newton s laws of motion and gravitation describe and predict the motion of most objects. 1.1 Compare and contrast vector quantities (e.g., displacement, velocity, acceleration, force, linear momentum) and scalar quantities (e.g., distance, speed, energy, mass, work). 1. Which of the following is a vector quantity? A. displacement B. speed C. mass D. distance 2. Which of the following statements identifies the main difference between vector and scalar quantities? A. Only vectors have direction. B. Only scalars have magnitude. C. Only scalars have units associated with them. D. Only vectors have units associated with them. 1.2 Distinguish between displacement, distance, velocity, speed, and acceleration. Solve problems involving displacement, distance, velocity, speed, and constant acceleration. 3. The diagram below shows the path of a jet from Washington, D.C. to Dallas, TX. 4. Jill drives from Newton to Boston. Her ending point is 5 miles due East of her starting point but she had to drive 7 miles total since roads don t go due East. Which of the following best describes the displacement Jill experienced? A. Jill was displaced 7miles. B. Jill was displaced 5 miles. C. Jill was displaced 7 miles East. D. Jill was displaced 5 miles East. The trip takes approximately 2 hours and covers approximately 1900 km. Which of the following best describes the average speed and direction of the jet s flight? A. 475 km/h southwest B. 950 km/h southwest C km/h southwest D km/h southwest

2 5. Which of the following cars is NOT accelerating? A. A car that is slowing down to a stop at a red light. B. A car that is traveling at a constant speed around a sharp curve. C. A car that is speeding up as it passes another car on the highway. D. None of the above. All of the cars described are accelerating. 6. The following table describes the distance a toy car travels. Time(s) Distance (cm) ? The car travels at a constant velocity for the first 2 seconds. If the toy car starts accelerating, which of the following could be the next distance in the table? A. 0cm B. 3cm C. 12cm D. 15cm 1.3 Create and interpret graphs of 1-dimensional motion, such as position vs. time, distance vs. time, speed vs. time, velocity vs. time, and acceleration vs. time where acceleration is constant. 7. The graph below relates distance to time for a rolling ball. 8. The graph below shows a beetle s movement along a plant stem. What is the average speed of the ball? A. 2 m/s B. 6 m/s C. 8 m/s D. 72 m/s During which span of time was the beetle not moving? A. from 0 to 4 minutes B. from 4 to 6 minutes C. from 6 to 14 minutes D. from 14 to 16 minutes

3 9. An object is traveling in a straight line. The graph below shows the object s velocity over time. 10. The graph below represents the motion of a car as it moves along a straight road for 20 s. Which line segment shows the object traveling with a constant, positive acceleration? A. segment W B. segment X C. segment Y D. segment Z Which statement best describes the motion of the car over the 20 s? A. The car is initially at rest and then backs up for 10 s. B. The car moves 20 m in the first 10 s and then stops. C. The car travels at a constant speed for 10 s and then decelerates until it stops. D. The car travels at a constant speed of 20 m/s and then decelerates until it is traveling at a constant speed of 15 m/s.

4 1.4 Interpret and apply Newton s three laws of motion. 11. You are driving along at a constant 20 miles per hour. Then you slam on the brakes. What happens to your books that are on the passenger side seat? A. The books stay on the seat. B. The books continue moving forward and fall on the floor. C. The books fly up in the air and end up in the back seat. D. The books slide across the seat and hit the door. 12. The illustration below shows a 2-ton elephant balancing on a tree stump. Which of the following statements must be accurate? A. The weight of the tree stump is greater than 2 tons. B. A 4-ton force on the ground spreads out in all directions. C. The tree stump is exerting a 2-ton force upward on the elephant. D. The downward force on the ground under the tree stump is 4 tons.

5 13. A mosquito flies into the oncoming windshield of a large truck. The truck exerts a force of 10 Newtons on the mosquito. What can we say about the force that the mosquito exerts on the truck? A. The mosquito exerts a force much less than 10N on the truck. B. The mosquito exerts a force exactly equal to 10N on the truck. C. The mosquito exerts a force much greater than 10N on the truck. D. Not enough information is provided. 14. You punch a wall. Afterwards your hand hurts so you know that the wall must have exerted a force on your hand. The wall didn t move or react. Did you exert a force on the wall? A. Yes, I exerted a force on the wall. Forces always occur in pairs. The force that I exerted is equal in magnitude and opposite in direction to the force that the wall exerted on me. B. Yes, I exerted a force on the wall. Forces always occur in pairs. The force that I exerted on the wall is much smaller than the force that the wall exerted on me which is why the wall doesn t move. C. No, I didn t exert a force on the wall. If I had exerted a force on the wall, the wall would have moved. D. No, I didn t exert a force on the wall. You can t exert forces on solid objects like walls. 15. A ball has a mass of 0.1 kg and an initial velocity of 20 m/s. The ball is given an acceleration of 30 m/s 2 for 5 s. What is the net force on the ball during acceleration? A. 0N B. 3N C. 10N D. 15N 16. A tiger football player with a mass of 100kg is running down the field. A player from the other football team exerts a force of 500N to the left on the tiger and the tiger experiences a friction force of 100N to the right during the tackle. What is the magnitude of the tiger s acceleration? A. 1m/s 2 B. 4m/s 2 C. 5m/s 2 D. 6m/s 2

6 1.5 Use a free-body force diagram to show forces acting on a system consisting of a pair of interacting objects. For a diagram with only co-linear forces, determine the net force acting on a system and between the objects. 17. The forces acting on a skateboarder moving at a constant velocity along a sidewalk are shown in the figure below. 18. An elastic cord made for bungee jumping is being tested. A weight of 800 N is attached to one end of the bungee cord. Then the weight is released from a tall tower and it moves downward. When the elastic cord is fully extended, it exerts an opposing force of 900 N on the weight. Which of the following is an accurate free-body diagram for this situation? A. B. 800N 800N Which of the following is the net force on the skateboarder? A. 0 N B. 70 N C. 670 N D N 800 N C. D. 800N 900 N 900 N 900N 800 N

7 1.6 Distinguish qualitatively between static and kinetic friction, and describe their effects on the motion of objects. 19. You place a block on a slide at the park. The block 20. An object that you are pushing with a force of 10 stays at rest on the slide. What force keeps the block Newtons is sliding at a constant velocity. What do in place? you know about the friction acting on the object? A. weight A. 10 N of kinetic friction are acting on the object. B. static friction B. 10 N of static friction are acting on the object. C. kinetic friction C. Less than 10N of static friction are acting. D. normal force D. Less than 10N of kinetic friction are acting. 1.7 Describe Newton s law of universal gravitation in terms of the attraction between two objects, their masses, and the distance between them. 21. One 7.0 kg bowling ball is lifted to a storage shelf 1.0 m above the floor. A second 7.0 kg ball is lifted to a storage shelf 2.0 m above the floor. Which of the following best explains why the measured force of gravity on each ball is nearly identical? A. The final potential energy of each ball increased. B. The amount of work required to lift each ball is identical. C. The distance of each ball from Earth s center of mass is almost identical. D. The gravitational force of each ball on the other cancels out the force of Earth s gravity. 22. On Earth, Johanna weighs 100 lbs. She calculated what her weight would be at several other locations in the solar system. The results are shown in the table below. Which of the following statements is best supported by the information in the table? A. Venus has more gravitational force than Earth. B. Mars has less gravitational force than the Moon. C. Earth has four times the gravitational force of Mars. D. Jupiter has more than twice the gravitational force of Earth.

8 1.8 Describe conceptually the forces involved in circular motion. 23. The diagram below shows a ball tied to a string. A student is swinging the ball in a horizontal circle. 24. The diagram below shows an object traveling at a constant speed in a circular path. If the student releases the string, in which direction will the ball travel? A. W B. X C. Y D. Z Which labeled arrow represents the centripetal force acting on the object? A. W B. X C. Y D. Z

9 2. Conservation of Energy and Momentum Central Concept: The laws of conservation of energy and momentum provide alternate approaches to predict and describe the movement of objects. 2.1 Interpret and provide examples that illustrate the law of conservation of energy. 25. The diagrams below show a man swinging a golf club. 26. A ball is thrown straight upward. The ball s initial speed is 30 m/s and its mass is 0.05 kg, resulting in an initial kinetic energy of 22.5 J. If the initial potential energy of the ball is 10 J and there is no frictional force, what would be the ball s total energy while it is moving? A. 0.0 J B J C J D J The kinetic energy of the golf club at point Y is more than the potential energy of the club at point X. Which of the following statements best explains why this fact does not violate the law of conservation of energy? A. Gravity is constant from point X to point Y. B. Air resistance is greater at point Y than at point X. C. Acceleration due to gravity is greater at point Y than at point X. D. Energy is added by the man to the golf club from point X to point Y.

10 2.2 Interpret and provide examples of how energy can be converted from gravitational potential energy to kinetic energy and vice versa. 27. Which one of the following objects has mechanical energy (KE +GPE) that remains constant? A. A crate being lifted vertically upwards at a constant velocity. B. An apple in free-fall. C. A car accelerating on a level(flat) highway. D. A sky-diver falling to Earth with his parachute open. 28. An astronaut drops a 1.0 kg object and a 5.0 kg object on the Moon. Both objects fall a total distance of 2.0 m vertically. Which of the following best describes the objects after they have fallen a distance of 1.0 m? A. They have each lost kinetic energy. B. They have each gained the same amount of potential energy. C. They have each lost the same amount of potential energy. D. They have each gained one-half of their maximum kinetic energy. 2.3 Describe both qualitatively and quantitatively how work can be expressed as a change in mechanical energy. 29. An archer pulls back the bowstring to prepare to shoot an arrow as shown below. 30. Work is performed on an object by raising it 2 m above the floor. Which of the following types of energy must change in this situation? A. chemical energy B. magnetic energy C. mechanical energy D. thermal energy She uses an average force of 40 N, moving the bowstring 0.2 m. How much energy is stored in the bow? A. 8 J B. 16 J C. 24 J D. 36 J

11 2.4 Describe both qualitatively and quantitatively the concept of power as work done per unit time. 31. At a weightlifting competition, two competitors lifted the same weight to the same height. The second competitor accomplished the lift 2 seconds faster than the first competitor. This demonstrated that the second competitor had more A. energy than the first. B. inertia than the first. C. power than the first. D. work than the first. 32. The table below provides information about the daily use of some typical appliances. Appliance Power Rating (W) dishwasher air conditioner Duration of Use (hr) laptop computer clock radio Which appliance uses the most energy? A. dishwasher B. air conditioner C. laptop computer D. clock radio 2.5 Provide and interpret examples showing that linear momentum is the product of mass and velocity, and is always conserved (law of conservation of momentum). Calculate the momentum of an object. 33. You are at an ice skating rink and are gliding towards a friend who is initially at rest. When you reach your friend, you grab your friend around the waist and the two of you continue gliding forward. Which one of the following is true: A. Your speed after the collision is greater than your speed before the collision. B. Your speed after the collision is the same as your speed before the collision. C. Your speed after the collision is smaller than your speed before the collision. D. Not enough information has been provided. 34. An object with a mass of 3 kg has a momentum of 75 kg m/s. What is its velocity? A. 0.4m/s B. 7.1m/s C. 25m/s D. 72m/s

12 Open Response: Please complete on a separate sheet of paper. BE SURE TO ANSWER AND LABEL ALL PARTS OF THE QUESTION. Show all your work (diagrams, tables, or computations). If you do the work in your head, explain in writing how you did the work. 1. A person is driving his car to a store. The store is 800 m north of the person s starting point. After traveling north 1200 m, the person realizes that he has passed the store. He turns the car around and drives back to the store. Altogether, the trip to the store takes 100s. a. Determine the distance traveled by the car on this trip to the store. Show your calculations and include units in your answer. b. Calculate the average speed of the car on this trip. Show your calculations and include units in your answer. c. Determine the displacement of the car for this trip. Include units in your answer. d. Calculate the average velocity of the car upon arrival at the store. Show your calculations and include units in your answer.

13 2. A book is on a table. A student pushes it for a short time. Initially the book moves, but then it comes to a complete stop. a. Identify the forces acting on the book before it is pushed. You may include a labeled diagram in your answer. b. Explain why the book moves and then comes to a complete stop. Use the laws of physics in your answer. c. The student wants the book to move at a constant speed in one direction. Describe the physical conditions needed for this to occur.

14 3. Students in a physics class are studying the energy changes that objects experience as they fall. The students plan to drop a metal sphere with a mass of 0.05 kg from a height of 20.0m onto a bed of sand. They predicted the results shown in the table below. Time (s) Speed (m/s) Distance Fallen (m) Height (m) a. Using the predicted values in the table, calculate the kinetic energy of the sphere just before it contacts the sand at 2.0 s. Show your calculations and include units in your answer. b. Using the predicted values in the table, calculate the gravitational potential energy at 0.0 s. Show your calculations and include units in your answer. c. Describe what happens to the gravitational potential energy and the kinetic energy as the sphere falls. d. After the sphere is dropped, the students find that the results of the experiment are slightly different than they predicted. Assuming the students performed their calculations correctly, explain one possible reason for the difference they observed.