Physics Unit of Speed Chapter 4 Test Answers

Physics Chapter 4 Test Name _______________________ Multiple Choice Identify the choice that best completes the statement or answers the question. Unless you are instructed otherwise, assume that all situations are on Earth at sea level. ____ 1. Speed is a. a measure of how fast something is accelerating. b. always measured in terms of a unit of time divided by a unit of distance. c. the distance covered per unit time. d. all of the above. e. none of the above. ____ 2. One possible unit of speed is a. kilometers per minute b. light-years per parsec. c. hours per kilometer. d. all of the above. e. none of the above. ____ 3. Acceleration is defined as the CHANGE in a. time it takes to move from one place to another place. b. velocity of an object. c. distance divided by the time interval. d. velocity divided by the time interval. e. time it takes to move from one speed to another speed. ____ 4. Suppose you are in a car that is going around a curve. The speedometer reads a constant 30 miles per hour. Which of the following is true? a. You and the car are accelerating. b. Your speed is constantly changing. c. Your velocity is constant. d. Your position is constant. ____ 5. A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. Its acceleration is a. 0 m/s2. b. 6 m/s2. c. 12 m/s2. d. 18 m/s2. e. none of the above ____ 6. As an object falls freely in a vacuum, its a. velocity increases. b. acceleration increases. c. both A and B. d. none of the above. ____ 7. In the absence of air resistance, objects fall at constant a. speed. b. velocity. c. acceleration. d. distances each successive second. e. all of the above ____ 8. A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be a. less than the speed it had when thrown upwards. b. more than the speed it had when thrown upwards. c. the same as the speed it had when thrown upwards. ____ 9. Suppose an object is in free fall. Each second the object falls a. the same distance as in the second before. b. a larger distance than in the second before. c. with the same instantaneous speed. d. with the same average speed. e. none of the above ____ 10. When a basketball player jumps to make a shot, once the feet are off the floor, the jumper's acceleration a. varies with body orientation. b. depends on launch speed. c. is usually greater for taller players (but not always). d. depends on all the above. e. is 10 m/s/s. ____ 11. If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by a. about 5 m/s. b. about 10 m/s. c. about 15 m/s. d. a variable amount. e. a rate that depends on its initial speed. ____ 12. A car starts from rest and after 7 seconds it is moving at 42 m/s. What is the car’s average acceleration? a. 0.17 m/s2 b. 1.67 m/s2 c. 6 m/s2 d. 7 m/s2 e. none of the above ____ 13. A ball is thrown straight up. At the top of its path its instantaneous speed is a. 0 m/s. b. about 5 m/s. c. about 10 m/s. d. about 20 m/s. e. about 50 m/s. ____ 14. A ball is thrown straight up at 40 m/s. Half way to its peak, the acceleration of the ball is a. 0 m/s2. b. about 5 m/s2. c. about 10 m/s2. d. about 20 m/s2. e. about 50 m/s2. ____ 15. A car accelerates at 3.6 m/s2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 42.8 m/s? a. 3.6 seconds b. 23.2 seconds c. 39.2 seconds d. 21.4 seconds e. none of the above ____ 16. Suppose you take a trip that covers 240 km and takes 3 hours to make. Your average speed is a. 40 km/h. b. 60 km/h. c. 80 km/h. d. 100 km/h. e. 120 km/h. ____ 17. A freely falling object starts from rest. After falling for 3.8 seconds, it will have a speed of about a. 3.8 m/s. b. 380 m/s. c. 72.2 m/s. d. 38 m/s. e. more than 380 m/s. ____ 18. If you drop a feather and a coin at the same time in a vacuum tube, which will reach the bottom of the tube first? a. Neither-they will both reach the bottom at the same time. b. The coin c. The feather ____ 19. If a projectile is fired straight up at a speed of 45 m/s, the total time to return to its starting point is about a. 4.5 seconds. b. 9 seconds. c. 13.5 seconds. d. 18 seconds. e. not enough information to estimate. ____ 20. Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of a. 1 m. b. 2 m. c. 3 m. d. 4 m. e. 5 m. ____ 21. A pencil lies on your desk. If the Earth is moving around the sun at a speed of 30 km/s, how fast is the pencil moving relative to the desk? How fast is the pencil moving relative to the sun? a. 0 km/s; 0 km/s b. 0 km/s; 30 km/s c. 30 km/s; 30 km/s d. There is not enough information to answer these questions. ____ 22. Acceleration is defined as a. the rate at which distance is covered b. the rate at which an object freely falls from rest c. the rate at which velocity itself changes d. the distance an object has fallen ____ 23. In a vacuum, a marble starts from rest and falls 32 m. How long does this take? a. 32 s c. 3.2 s b. 6.4 s d. 2.5 s ____ 24. Velocity differs from speed in that velocity a. has no direction. b. has no magnitude. c. has direction. d. has magnitude. ____ 25. A unit of velocity is a. meter b. second c. second per meter d. meter per second. ____ 26. A unit of acceleration is a. meters per second b. meters per second squared c. meters d. seconds per meter ____ 27. When a vehicle moves around a corner at constant speed a. the velocity is constant. c. the vehicle accelerates. b. the acceleration is zero. d. the vehicle slows down. ____ 28. A ball is thrown in the air. At the peak of its flight a. velocity and acceleration are zero. c. velocity is nonzero and acceleration is zero. b. velocity is zero and acceleration is d. velocity and acceleration are nonzero. nonzero. ____ 29. A bicycle is traveling at 10 m/s on a flat road. As it reaches a hill, it starts accelerating, eventually reaching 36 m/s. What is its average speed on the hill? a. 18 m/s c. 5 m/s b. 23 m/s d. 13 m/s ____ 30. What is the average acceleration of a car that goes from 49 kph to 93 kph in 4 seconds? a. 11 km/hr/s c. 12 km/hr/s b. 22 km/hr/s d. 36 km/hr/s ____ 31. A jet on an aircraft carrier can be launched from rest to 40 m/s in 2 seconds. What is the acceleration of the aircraft? a. 2 m/s/s c. 80 m/s/s b. 20 m/s/s d. .05 m/s/s ____ 32. A ball is dropped from rest from a height of 38 m. It reaches the ground 2.8 seconds later. What is the average speed of the ball? a. 14 m/s c. 38 m/s b. 2.8 m/s d. 28 m/s ____ 33. A ski jumper starts from rest and accelerates down a ramp at 3.1 m/s/s for 5.6 seconds. What is the final speed of the ski jumper? a. 8.7 m/s c. 1.8 m/s b. 17.4 m/s d. 21.6 m/s ____ 34. A younger runner gets a 12 m head start in a race. If the runner’s speed is 3.8 m/s, how far is the runner from the starting line after 49 seconds? a. 198 m c. 174 m b. 186 m d. 210 m ____ 35. An apple falls for 3.6 seconds before hitting the ground. How fast is the apple falling at the instant it hits the ground? a. 3.6 m/s c. 24 m/s b. 18 m/s d. 36 m/s ____ 36. What speed must you toss a ball straight up to have it come back to you in 7 seconds? a. 7 m/s c. 30 m/s b. 21 m/s d. 35 m/s ____ 37. If you throw a ball straight up at 24 m/s, how long will it take to reach its peak? a. 1.2 s c. 2.4 s b. 4.9 s d. 7.2 s ____ 38. A ball is thrown straight down at 6 m/s. How long will it take for the rock to reach a velocity of 32 m/s? a. 3.2 s c. 3.8 s b. 2.6 s d. 26 s ____ 39. Starting from rest, a car undergoes constant acceleration of 12 m/s/s. How far does the car travel in 2 seconds? a. 4 m c. 12 m b. 6 m d. 24 m ____ 40. How much time does it take for a car with acceleration of 8 m/s/s to go from 62 m/s to 147 m/s? a. 26 s b. 18 s c. 8 s d. 11 s Physics Chapter 4 Test Answer Section MULTIPLE CHOICE 1. ANS: C KEY: speed | distance | time 2. ANS: A KEY: speed | unit 3. ANS: D KEY: acceleration | velocity 4. ANS: A KEY: velocity | constant | speedometer 5. ANS: A KEY: acceleration 6. ANS: A 7. KEY: vacuum | fall ANS: C KEY: air | resistance | acceleration 8. ANS: C KEY: air | resistance | speed 9. ANS: B 10. ANS: E KEY: free fall KEY: acceleration | hang time 11. ANS: B KEY: speed | falling 12. ANS: C 13. ANS: A 14. ANS: C KEY: acceleration KEY: instantaneous | speed KEY: acceleration 15. ANS: E KEY: acceleration 16. ANS: C KEY: speed | average 17. ANS: D KEY: free fall | speed 18. ANS: A KEY: vacuum | fall 19. ANS: B KEY: projectile | speed 20. ANS: E KEY: hang time | distance 21. ANS: B KEY: motion | relative 22. ANS: C 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. KEY: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: acceleration D C D B C B B A B A B A D D C B C D