Exam Unit 5: Motion and Forces

Transcription

1 Exam Unit 5: Motion and Forces 1. Aleshia is moving forward at constant speed of 2 m/s. Which statement correctly describes Aleshia s movement? A. Her speed is increasing by 2 m/s every second. B. She is moving forward 2 meters every second. C. Her speed is increasing by 1 m/s every second. D. She is moving forward 1 meters every 2 seconds. 2. Chermanika steals a car from a parking lot, and she drives away fast. She drives a total distance of 600 m from the parking lot. This takes her 20 seconds. What was her average speed during this drive? A. 300 m/s B m/s C. 30 m/s D. 1/30 m/s 3. Trent Richardson has a break-out run against LSU: he runs for 60 meters in 5 seconds. What is his average speed during the run? A. 60 m/s B. 300 m/s C. 30 m/s D. 12 m/s 4. Indianapolis Colts quarterback Andrew Luck is facing a tough pass rush, so he decides to run instead of pass. He runs at an average speed of 10 meters per second (10 m/s), and he runs for 6 seconds. How many meters did he run for? A. 60 m B m C. 0.6 m D. 30 m 5. New York Knicks point guard (and former classmate of Mr. D) Jeremy Lin gets a steal against the Heat and runs down court. He runs at an average speed of 12 meters per second (12 m/s), and he runs for a total distance of 24 m. How long does this run take him? A. 2 s B. 0.5 s C. 288 s D. 4 s 6. A car is accelerating at a rate of 10 m/s 2. Which statement correctly describes the movement of this car? A. It is moving forward 10 meters every second. B. Its speed is increasing by 1 m/s every 10 seconds. C. It is moving forward 1 meter every 10 seconds. D. Its speed is increasing by 10 m/s every second. 7. Jalayvian is standing still on the line of scrimmage in a football game. After the play begins, he begins running. After 2 seconds, he has reached his top speed of 6 m/s. During those 2 seconds, what was Jalayvian s rate of acceleration? A. 3 m/s 2 B. 2 m/s 2 C. 0 m/s 2 D. 6 m/s 2 8. William is driving his truck at 25 m/s to go to work, but then he notices he is late. He presses down on the accelerator, and he increases his speed to 55 m/s over the next 5 seconds. What was his rate of acceleration during this time? A. 180 m/s 2 B. 11 m/s 2 C. 5 m/s 2 D. 6 m/s 2

2 9. Amarekia is running a race against Lakeya. They both start at a speed of 0 m/s on the starting line of the race. When the race begins, Amarekia accelerates at a rate of 2 m/s 2. If Amarekia keeps this rate of acceleration, what will her speed be after 3 seconds? A. 2 m/s B m/s C. 6 m/s D. 1.5 m/s 10. Edward is riding a bicycle at a speed of 10 m/s. He sees a stop sign up ahead, so he presses down on the brakes. He comes to a complete stop in 5 seconds. What was his acceleration during this time? A. 50 m/s 2 B. 2 m/s 2 C. 0 m/s 2 D. 2 m/s 2 The following distance-time graph shows how much distance Brian walked during PE class. Use the graph to answer questions After 5 seconds, how many meters had Brian walked? A. 5 m B. 10 m C. 50 m D. 2 m 12. What was Brian s speed from 5 seconds to 10 seconds? A. 5 m/s B. 0.5 m/s C. 2 m/s D. 15 m/s 13. What was Brian s speed from 25 seconds to 30 seconds? A. 30 m/s B. 6 m/s C. 3 m/s D. 15 m/s 14. During what segment was Brian not moving? A. Segment A B. Segment B C. Segment C D. Segment D 15. During what segment was Brian s speed the fastest? A. Segment A B. Segment B C. Segment C D. Segment D

3 The following velocity-time graph shows how Raheem s velocity changes as he drives a car along Interstate 20. Use the graph to answer questions After 2 seconds, what was Raheem s speed? A. 5 m/s B. 10 m/s C. 20 m/s D. 2 m/s 17. What was Raheem s rate of acceleration for the first two seconds of his drive? A. 10 m/s 2 B. 20 m/s 2 C. 5 m/s 2 D. 0 m/s What was Raheem s rate of acceleration from 4 seconds to 6 seconds? A. 4 m/s 2 B. 3 m/s 2 C. 4 m/s 2 D. 3 m/s From 2 seconds to 4 seconds, what was Raheem doing? A. He was not moving. B. He was moving forward at a constant speed of 10 m/s. C. He was moving backward at a speed of 10 m/s. D. He was moving forward at a speed of 5 m/s. 20. Which statement correctly describes Raheem s movement from 4 seconds to 6 seconds? A. He was slowing down. B. He was speeding up. C. He was moving backwards. D. He was not moving.

4 21. The diagram to the right shows the forces acting on a rock. The force of gravity exerts a downward force of 76 N. An upward force of 106 N is also exerted on the rock. What is the net force acting on the rock? A. 30 N upward B. 76 N downward C. 106 N upward D. 182 N downward 22. Three forces are acting on the box below, as shown. What is the net force acting on the box? A. 4 N to the left B. 20 N to the right C. 4 N to the left D. 20 N to the right 23. Four students push on a block of wood with the forces shown in the diagram to the right. Assume no other forces act on the block. The block slides horizontally. What is the net force acting on the block of wood? A. 3 N to the left B. 8 N to the left C. 11 N to the right D. 25 N to the right 24. The picture to the right shows a toy car at rest. Two forces are applied to the car, as shown in the diagram. Assume no other forces act on the car. Which statement correctly describes what will happen to the car? A. The car will accelerate. B. The car will move forward at a constant velocity. C. The car will remain at rest. D. The car will move forward with a constant acceleration. 3 N 3 N

5 Use the diagram below to answer questions Two forces are applied to a truck, as shown in the diagram. The truck s engine applies a 100 N force to the right, while the combination of friction and air resistance apply a 60 N force to the left. Assume no other forces act on the truck. 25. What is the net force acting on the truck? A. 0 N B. 290 N C. 110 N D N 200 N 90 N 26. Which statement correctly describes the truck s motion? A. The truck will accelerate to the right. B. The truck will move to the right at a constant velocity. C. The truck will accelerate to the left. D. The truck will move to the left at a constant velocity. Use the information and diagram below to answer questions 7-8. The forces acting on a skateboarder moving at a constant velocity along a sidewalk are shown in the figure. 27. Which of the following is the net force on the skateboarder? A. 0 N B. 70 N C. 670 N D N 28. If these two forces continue to act on the skateboarder, what will happen to his velocity? A. His velocity will increase. B. His velocity will decrease. C. His velocity will immediately change to 0 m/s. D. His velocity will stay the same. 29. An airplane in flight is acted on by four forces. Drag is air resistance, lift is the upward force provided by the wings, thrust is the forward force provided by the plane s engines, and weight is the downward force of gravity acting on the plane. For this plane to continue to fly directly forward at a constant speed, which pair of forces must be equal? A. lift and drag B. drag and weight C. thrust and drag D. thrust and lift

6 Use the diagram below to answer questions The following drawing shows a water skier at different stages. Picture 1 shows the skier floating still in the water. Picture 2 shows the skier being pulled out of the water as the boat begins to move. Picture 3 shows the skier being pulled at a constant velocity. Picture 4 shows the skier letting go of the rope. 30. When does the water skier experience acceleration (in any direction)? A. Point 1 only B. Points 1 and 3 C. Point 2 only D. Points 2 and Which statement correctly describes the net force in Picture 3? A. A net force is causing the skier to accelerate to the right. B. A net force is causing the skier to accelerate to the left. C. A net force is pulling the skier to the right at a constant velocity. D. There is no net force acting on the skier. Use the information and diagram below to answer questions A car is pulling a trailer. The car s engine exerts a 6000 N force pulling the car to the left. In addition, the car and the trailer each experience a 1000 N frictional force as they are being pulled, as shown. Assume no other forces act on the car and trailer. 32. What is the net force on the car and trailer? A N B N C N D N 33. Which statement best describes the car and trailer s motion? A. They will move to the left at a constant velocity. B. They will move to the left and their speed will decrease. C. They will move to the left and their speed will increase. D. They will remain at rest. 34. Together, the car and trailer have a mass of 2000 kg. If the net force acting on the car and trailer stays the same as above, at what rate will the car and trailer accelerate? A. 2 m/s 2 B m/s 2 C. 0.5 m/s 2 D. 3 m/s A 50-kg boulder is being pulled by a pack of dogs. The boulder is accelerating at a rate of 2 m/s 2. What is the net force acting on the boulder? A. 0 N B. 100 N C. 25 N D. 250 N

7 36. Qwundre pushes with a net force of 20 N on a box that has a mass of 4 kg. What is the rate of acceleration of the box? A. 80 m/s 2 B. 40 m/s 2 C. 5 m/s 2 D. 0 m/s Norman pushes Mr. D with a net force of 400 N, causing Mr. D to accelerate at a rate of 5 m/s 2. What is Mr. D s mass? A. 80 kg B kg C. 90 kg D. 200 kg 38. A 200-kg sumo wrestler is shoved by his opponent. The push causes him to accelerate backward at 2 m/s 2. What is the net force that acted on the wrestler? A. 0 N B. 40 N C. 100 N D. 400 N 39. The diagrams below show smooth blocks of wood being pushed across the same surface. The mass of the block and amount of force applied are labeled in each diagram. In which diagram would the block of wood have the greatest acceleration? A B C D 40. What will be the acceleration of the box to the right? A. 3 m/s 2 to the right C. 0.5 m/s 2 to the right B. 2 m/s 2 to the left D. 800 m/s 2 to the right 41. Which of the objects will fall at the fastest rate when dropped? A. The ball with a mass of 75 kg. B. The ball with a mass of 25 kg. C. The ball with a mass of 10 kg. D. They all fall at the same rate. 42. A man with a mass of 50 kg jumps out of an airplane and begins falling toward Earth due to gravity. Assume that gravity is the only force acting on the person. What is the force of gravity that the man has as he is falling? (You may round the rate of acceleration due to gravity to the nearest whole number). A. 500 N B. 5 N C. 2 N D. 800 N 43. A man with a mass of 60 kg falls off the top of a building and accelerates toward Earth due to gravity. What is the force of gravity that the man has as he is falling? (You may round the rate of acceleration due to gravity to the nearest whole number). A. 60 N B. 600 N C. 6 N D. 0 N 44. A crate is thrown out of a plane and begins accelerating toward Earth due to gravity. The force of gravity acting on the box is 450 N. What is the mass of the box? A. 4.5 kg B kg C. 45 kg D. 2.1 kg

8 45. Wherever there is an action force, there must be a reaction force that A. is equal to the action force and acts in the same direction. B. is smaller than the action force and acts in the opposite direction. C. is larger than the action force and acts in the same direction. D. is equal to the action force, but in the opposite direction. 46. A soccer player kicks a 3-kg ball with 60 N of force. What is the force that acts on the player s foot? A. 180 N B. 20 N C. 60 N D. 0 N 47. A rocket ship shooting off Earth fires its engines down to the ground with 1,000,000 N of force at lift-off. Which statement best describes what happens when the rocket does this? A. The rocket goes up with 1,000 N of force because of gravity. B. The rocket goes up because the ground presses up on it with 1,000,000 N of reaction force. C. The rocket goes up because the ground presses up on it with 500,000 N of reaction force. D. The rocket does not move. 48. A basketball bounces because A. the reaction force of the ground pushes up on the ball. B. gravity pushes down on the ball. C. Inertia stops the ball from going through the ground. D. F = ma. 49. Look at the picture below. Skater A has a mass of 50 kg, and skater B has a mass of 25 kg. Skater A pushes on Skater B with a force of 100 N. (Skater B does not exert any force on Skater A). With what rate of acceleration will Skater A move backward? Skater A Skater B 100 N A m/s 2 C. 2 m/s 2 B. 4 m/s 2 D m/s Look at the picture to the right. The book on the table has a normal force (the reaction force pushing UP on the book) of 50 N. What is the force of gravity pulling DOWN on the book? A. 50 N B. 500 N C. 5 N D. 0 N 50 N