Physics Exam 1 Sample Exam
1. A bowling ball falls freely from rest for 10 seconds before it hits the ground. Neglect air resistance.
a) Is the acceleration of the ball during the first 5 seconds greater than, less than, or the same as the acceleration of the ball during the last 5 seconds?
b) Is the average speed of the ball during the first 5 seconds greater than, less than, or the same as the average speed of the ball during the last 5 seconds?
c) Is the distance traveled by the ball during the first 5 seconds greater than, less than, or the same asthe distance traveled during the last 5 seconds?
d) How fast is the ball falling just before it hits the ground?
e) What is the ball’s average speed for its fall?
f) How far did the ball fall?
2. A marble rolls off a table (95 cm high) and lands on the floor 3.2 meters from the edge of the table. If the perfectly level table is 1.4 meters long, how long did it take the ball to roll across the table? What assumptions have you made in answering this question?
3. A batter hits a pop fly straight up. The catcher catches 4.6 s later it at the same height that the batter hit it.
a) How high did the ball go?
b) How fast was the ball going when it left the bat?
4. A train is moving at 40 m/s when the engineer applies the brakes. The train stops right at the station in 20 seconds. (a) What negative acceleration do the brakes apply to the train? (b) What was the train’s average speed during that 20 seconds? (c) How far was the train from the station when it started braking?
Questions 5-12 refer to the following set of speed-time graphs. On your answer sheet, write the letter(s) of the graph(s) that represent the kind of motion described. There may be more than one letter for each answer. If there are no graphs for which the description is true, write "none."
5. moving at a constant speed
6. increasing speed in either direction
7. moving in the positive direction
8. moving in the negative direction
9. standing still
10. decreasing speed in either direction
11. moving in the negative direction at a constant speed
12. moving in the positive direction with a changing speed
Questions 13-19 refer to the following set of distance-time graphs. On your answer sheet, write the letter(s) of the graph(s) that represent the kind of motion described. There may be more than one letter for each answer. If there are no graphs for which the description is true, write "none."
13. standing still
14. changing speed in either direction
15. increasing speed in either direction
16. moving in the negative direction
17. moving like a freely-falling object in a vacuum
18. decreasing speed toward the origin
19. moving with a constant speed
20. Compare Galileo’s Law of Falling Bodies with Einstein’s Theory of Special Relativity. What do they have in common? What problem(s) prompted each theory? What assumptions does each make? What are some of the consequences of each?
21. Four of the labs we have done in the class have been related to each other: Galileo, Freefall, Coffee Filter, and 2D Motion. In what ways do these labs form a sequence? How does that sequence advance your understanding of motion?
Additional Review Problems
22. A car is following a truck at 20 m/s. When the car goes to pass the truck, it needs to get up to 28 m/s and has 4 seconds to do it. (a) What acceleration does the car need? (b) What will its average speed be during that time? (c) How far will the car move during that time?
23. Rank the following 5 accelerations from least (1) to greatest (5).
The acceleration due to gravity at the earth’s surface / ______The average acceleration of a feather falling through the air / ______
The acceleration of a marble rolling down a 75 ramp / ______
The acceleration of a marble rolling across a horizontal table / ______
A change in velocity of 40 m/s in 2 seconds / ______
24. You stand at the top of a cliff and throw a rock horizontally at 1.8 m/s. You then hurry down to find your rock and you see that it is 6.4 meters from the base of the cliff. How tall is the cliff?
25. You are traveling in a convertible with the top down. The car is moving at a constant velocity of 25 m/s, due east along flat ground. You throw a tomato straight upward at a speed of 11 m/s. How far has the car moved when you get a chance to catch the tomato?
26. A car traveling 90 km/h is 100 m behind a truck traveling at 60 km/h. How long will it take the car to reach the truck?
27. During a hard sneeze, your eyes might shut for 0.5 s. If you are driving a car at 90 km/h, how far does it move during that time?
28. Bugs Bunny drops a cannon ball directly toward the head of the unsuspecting Yosemite Sam. It hits him 8.5 seconds after Bugs drops it.
a) Draw a speed-time graph of the motion of the ball.
b) Draw a distance-time graph of the motion of the ball.
c) How far was Bugs above the unfortunate Sam when he dropped the ball?
d) How fast was the ball moving when it conked Sam on the noggin?
29. (a) You walk 240 ft at a speed of 4 ft/s and then run 240 ft at a speed of 10 ft/s along a straight track. What is your average velocity?
(b) You walk for 1 min at a speed of 4 ft/s and then run for 1 min at a speed of 10 ft/s along a straight track. What is your average velocity?
30. You are driving a car that has a maximum acceleration (and deceleration) of 4 m/s/s and a maximum speed of 40 m/s. You are making a trip of 3000 m, during which you obey all speed limits and acceleration limits, of course.
(a) If there is a speed limit of 32 m/s but no acceleration limit, what is the minimum time for your trip?
(b) If there is an acceleration limit of 2.5 m/s/s but no speed limit, what is the minimum time for your trip?
(c) If both the speed limit and the acceleration limit are enforced, what is the minimum time for your trip?
31. Jimmy launches his rocket straight up with an initial velocity of 25 m/s.
(a) What is the velocity as the rocket reaches maximum height?
(b) How long will it take the rocket to reach its maximum height?
(c) Draw a distance vs. time graph showing the position of the rocket over the total time.
(d) Draw a velocity vs. time graph showing the velocity of the rocket over the total time.
(e) Draw an acceleration vs. time graph showing the acceleration of the rocket over the total time.
32. Shean releases Ultra Lord with a horizontal velocity of 3 m/s from a height of 7.0 m.
(a) How long until Ultra Lord reaches the ground?
(b) How far does Ultra Lord travel horizontally?
(c) Draw a velocity vs. time graph showing the vertical velocity of Ultra Lord.
(d) Draw a velocity vs. time graph showing the horizontal velocity of Ultra Lord.
33. An astronaut wearing a spacesuit can jump 0.5 m vertically at the surface of the earth. The gravitational acceleration on Mars is 0.4 times that on the earth. If her takeoff velocity is the same, how high can the astronaut jump on Mars?
34. A person who is properly constrained by a shoulder belt has a good chance of surviving a car collision if the deceleration does not exceed 300 m/s/s. Assuming uniform deceleration at this rate, calculate the distance over which the front end of the car must be designed to collapse if a crash occurs at 100 km/h.
Answers
1d 100 m/s
e50 m/s
f500 m
20.19 s
3a26.45 m
b23 m/s
4a2 m/s/s
b20 m/s
c400 m
5AB
6CF
7ACE
8BDF
9none
10DE
11B
12CE
13B
14ADEF
15AD
16DF
17A or D
18EF
19C
22a2 m/s/s
b24 m/s
c96 m
234, 2, 3, 1, 5
2463.2 m
2555 m
2612 s
2712.5 m
28c361.25 m
d85 m/s
29a5.7 ft/s
b7 ft/s
30a101.75 s
b69.3 s
c106.6 s
31a0 m/s
b2.5 s
32a1.18 s
b3.55 m
333 m
341.3 m