South Pasadena Chemistry s7

South Pasadena • Physics Name ______Period ___ Date ___/___/___ 2  Linear Motion Practice Test

DIRECTIONS  Please use a pencil to complete this test. A scientific calculator is allowed. No other resources are permitted.  Please show all work neatly for free response computational problems. Include all the appropriate units and show how they work out. Any answer without adequate work will not be given full credit. Answers should be recorded with the two significant figures, the correct direction (+ or –, if applicable), and units.  Work does not need to be shown for true or false and multiple choice questions.  Assume that “up” or “right” is the positive direction, and “down” or “left” is the negative direction. Assume that air resistance is negligible, unless otherwise specified. Use g = 9.8 m/s2, unless otherwise specified. FORMULAS

d = vt d = t v = vo + at 2 2 2 d = vot + ½ at v = vo + 2ad 7. A ball is thrown straight up into the air. Ignore True or False Questions (T or F) T F 1. A car that is changing direction at constant the affect of air resistance on the ball. At the top speed has constant velocity. of its path its acceleration is

T F 2. Speed is the rate at which distance covered a) about -20 m/s2 c) 0 m/s2 changes. b) about -10 m/s2 d) about -50 m/s2

T F 3. The steering wheel, accelerator and brakes of a car control speed. 8. A student wants to measure their friend’s reaction time. If the student drops a ruler through the T F 4. The rate at which velocity changes with fingers of the friend and the friend catches the time is called acceleration. ruler after 9.0 centimeters have passed through T F 5. A heavy hammer and a feather would fall the fingers, what is the reaction time of the at the same rate of acceleration if they friend? (remember, check units) were dropped on the surface of the moon. a) 0.14 seconds c) 0.35 seconds b) 0.18 seconds d) 1.4 seconds Multiple Choice Questions 9. A ball is thrown upward from a cliff with an initial 6. Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 velocity of 30.0 m/s. What is the velocity of the km/hr to 40 km/hr in the first second and from 40 ball 4.0 seconds after being thrown? Ignore air 2 km/hr to 45 km/hr in the next second. What is the resistance and let g = – 9.8 m/s . car’s acceleration? a) –9.2 m/s c) –12.5 m/s a) 40 km/h-s c) 10 km/hr-s b) –9.9 m/s d) –15.6 m/s b) 35 km/hr-s d) 5 km/hr-s 10. What is the displacement of the ball from the previous question, after the 4.0 seconds?

a) 200 meters c) 50 meters b) 40 meters d) - 65 meters 11. One possible unit of speed is e) Its position is left of the origin. a) miles per hour b) kilometers per hour c) megamile per century d) all of the above

12. A student is driving a sports car down a highway at a speed of 25.0 m/s. The driver comes up 16. An object’s velocity is its behind a slow-moving dump truck and decides to pass it on the left hand lane. If the driver can a) Change in acceleration

2 accelerate at a rate of 5.00 m/s , how much time b) Change in position will it take for him to reach a speed of 35.0 m/s? c) Displacement per unit time a) 2.00 s c) 3.00 s d) Speed b) 2.50 s d) 3.80 s e) Speed per unit time 13. Consider a row of Dominos that is lined up in a straight line on a table. If the average rate of their toppling speed is measured to be 65 centimeters 17. An object is moving with a velocity of –3 m/s per second, what length of dominoes would be and an acceleration of +3 m/s2 at a particular required to make it take 1.0 minute to fall? time. Which of the following best describes (Before | | | | | | | | | | | After / / / / / / / / / / / ) the object’s motion?

a) 8.5 meters c) 21 meters a) It is not moving b) 31 meters d) 39 meters b) It is moving at a constant velocity

c) It is speeding up (accelerating)

2 14. The measurement of 35 ft/s is a(n) d) It is slowing down (decelerating)

a) Acceleration e) It is slowing down then speeding up b) Displacement

c) Position Questions 18-20: Jon walks 50 m due east in 30 min with a constant speed. He then turns around and walks d) Time 80 m due west in 45 min. e) Velocity

18. What is Jon’s displacement? 15. If an object has a negative acceleration, a) –130 m a) It is being pulled toward the left. b) –30 m b) It is impossible to have a negative c) 0 m acceleration. d) 30 m c) It is moving toward the left. e) 130 m d) It is slowing down. 22. What is the ball’s displacement when it returns to 19. What is the distance of Jon’s travel? the ground?

a) – 130 m a) –40 m

b) –30 m b) – 10 m

c) 0 m c) 0 m

d) 30 m d) +10 m

e) 130 m e) +40 m

20. Which of the following expressions can be used to 23. What is the velocity the moment before it hits the find the average speed (in m/min) of Jon’s entire ground? journey? a) –40 m/s a) b) – 10 m/s b) c) 0 m/s c) d) +10 m/s d) e) +40 m/s e)

24. What is the acceleration the moment before it hits 21. A coin takes less time to fall to the ground than a the ground? feather. However, in a vacuum, it takes the same amount of time for the both to fall the same a) –40 m/s2 distance. Which of the following best accounts for b) – 10 m/s2 this observation? a) Air slows down the coin’s motion less than it c) 0 m/s2 does the feather’s. d) +10 m/s2 b) The acceleration due to gravity is greater for the coin than for the feather. e) +40 m/s2

c) The coin is heavier (has a greater mass) than the feather. 25. For how much time is the ball in the air? d) The surface area of the coin is less than the a) surface area of the feather. 2 s

b) e) There is no gravity in a vacuum. 4 s c) 6 s

d) 8 s

e) 10 s Questions 22-25: A ball is tossed up from the ground with an initial velocity of 40 m/s. Use g = 10 m/s2. Questions 26-28: Use the following graph. The intervals along the x axis are 1 s. The intervals along the y-axis are 1 m/s. y t i c o l e v

26. At t = 1 s, the object must be:

a) Moving at constant speed

b) Not moving

c) Slowing down

d) Speeding up

e) Cannot be determined from the graph

27. At t = 4 s, the object is:

a) Not moving

b) Moving at a constant velocity

c) Speeding up (accelerating)

d) Slowing down (decelerating)

e) Cannot be determined from the graph

28. What is the object’s velocity at t = 4 s?

a) 0 m/s

b) 0.75 m/s

c) 1.5 m/s

d) 2.25 m/s

e) 3.0 m/s