HS Dynamics Test 2010

D'Amato/Chia Physics Dynamics Test 2009 Page 1 of 8

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High School Dynamics Test

Part 1: This part consists of several multiple-choice questions. Please select the best answer or answers. If you

would like to explain your answer for any question, please use the space provided next to the question (this is

optional).

Q1. A book is at rest on a tabletop. Which of the following force(s) is(are) exerted on the book?

I A downward force exerted by the Earth on the book.

II An upward force exerted by the table on the book.

III A downward force exerted by the book on the table.

IV A net downward force due to air pressure.

1 I only

2 I and II

3 I, II, and III

4 I, II, and IV

5 None of these, since the book is at rest there are no forces exerted on it.

Q2. A TV box of constant mass slides on a very smooth floor. A person exerts a force on the box to the left and

parallel to the floor. The acceleration of the box is recorded. Additional trials are conducted; each time the

force exerted on the TV box is increased and the acceleration is recorded.

A graph is created for the acceleration of the TV box versus the unbalanced force exerted on the box. Choose

the graph that would best represent this experiment.

1

2

3

4

5 None of these

6 The answer cannot be determined from the

information given



Q3. Two students sit in identical office chairs facing each other. Bob has a

mass of 95 kg, while Jim has a mass of 77 kg. Bob places his bare feet on

Jim’s knees, as shown to the right. Bob then suddenly pushes outward

with his feet, causing both chairs to start moving. In this situation, while

Bob’s feet are in contact with Jim’s knees:

1 neither student exerts a force on the other.

2 Bob exerts a force on Jim, but Jim doesn’t exert any force on Bob.

3 each student exerts a force on the other, but Jim exerts the larger force.

4 each student exerts a force on the other, but Bob exerts the larger force.

5 each student exerts the same amount of force on the other.

Q4. A large box is being pushed across the floor. The box moves quickly at a constant speed of 4.0 m/s. What can

you conclude about the forces exerted on the box?

1 If the force exerted on the box is doubled, the constant speed of the box will increase to 8.0 m/s.

2 The force exerted by the person on the box must be greater than the force exerted by the Earth on the box.

3 The force exerted by the person on the box must be equal to the force the surface exerts on the box (friction).

4 The force exerted by the person on the box must be greater than the force the surface exerts on the box

(friction).

5 There is a force being exerted on the box to make it move but the external forces such as friction are not “real”

forces, they just resist motion.

Q5. If the person stops exerting a force on the box in the previous problem, the box will:

1 stop immediately.

2 continue at a constant speed for a very short period of time and then slow to a stop.

3 immediately start slowing to a stop.

4 continue at a constant velocity.

5 increase its speed for a very short period of time, then start slowing to a stop.



Question set

The next three questions refer to a coin which is tossed straight upward. After it is released, it moves upward,

reaches its highest point and falls back down again. Use one of the following choices to indicate the direction

of the unbalanced force exerted on the coin for each of the cases described. Ignore any effects of air resistance.

1 The unbalanced force is down and constant.

2 The unbalanced force is down and increasing.

3 The unbalanced force is down and decreasing.

4 The unbalanced force is zero.

5 The unbalanced force is up and constant.

6 The unbalanced force is up and increasing.

7 The unbalanced force is up and decreasing.

8 None of these is correct.

Q6. The coin is moving upward after it is released.

Q7. The coin is at its highest point.

Q8. The coin is moving downward.

Question set

Refer to the unlabelled force diagrams below. Choose the best response for each of the scenarios described below.

You may use each response once, more than once, or not at all.

1 2 3 4 5

6 More than one of the above

could match 7 None of the above could match

8 The answer cannot be

determined from the

information given

Q9. A person is falling on a trampoline.

Q10. A ball is held at rest in your hand.

Q11. The Voyager spacecraft is very far away from the Earth, the Sun, and the other planets. The propulsion system

is turned off. It is moving very fast through empty interstellar space.

Q12. An elevator hanging from a cable begins moving downward from rest when a button is pressed.

Q13. An elevator hanging from a cable is moving downward at a constant speed.

Q14. An elevator hanging from a cable is moving upward at a constant speed.



Question set: sled

A sled moves on ice in the ways described in the questions. Friction is so small that it can be ignored. A person

wearing spiked shoes standing on the ice can exert a force on the sled and push it along the ice.

Choose from among these responses for the NEXT FIVE QUESTIONS. You may use each response

once, more than once, or not at all.

1 The person exerts a force on the sled towards the right. The

force is increasing in strength (magnitude).


force is of constant strength (magnitude).


force is decreasing in strength (magnitude).

4 No force is exerted on the sled.

5 The person exerts a force on the sled towards the left. The

force is decreasing in strength (magnitude).


force is of constant strength (magnitude).


force is increasing in strength (magnitude).

8 None of these forces would produce the motion described

9 More than one of these forces could produce the motion

described

Q15. Which force would keep the sled moving toward the right and speeding up at a constant acceleration?

Q16. Which force would keep the sled moving toward the right at a steady (constant) velocity?

Q17. The sled is moving toward the right. Which force would slow it down at a constant acceleration?

Q18. Which force would keep the sled moving toward the left and speeding up at a constant acceleration?

Q19. The sled is moving toward the left. Which force would slow it down at a constant acceleration?



Question set: collisions

Choose from among these responses for the NEXT FIVE QUESTIONS. You may use each response once, more

than once, or not at all.

1 The truck exerts a greater amount of force on the car than the car exerts on the truck.

2 The car exerts a greater amount of force on the truck than the truck exerts on the car.

3 Neither exerts a force on the other; the car gets smashed simply because it is in the way of the truck.

4 The truck exerts a force on the car but the car doesn’t exert a force on the truck.

5 The truck exerts the same amount of force on the car as the car exerts on the truck.

6 None of the answers above describes the situation correctly

7 The answer cannot be determined from the information given

In the next three questions the truck is much more massive

than the car

Q20. They are both moving at the same speed as they collide. Which choice describes the forces?

Q21. The car is moving much faster than the more massive truck as they collide. Which choice describes the forces?

Q22. The heavier truck is standing still when the car hits it. Which choice describes the forces?

In the next two questions the truck is a small pickup and has the same

mass as the car

Q23. Both the truck and the car are moving at the same speed as they collide. Which choice describes the forces?

Q24. The truck is standing still when the car hits it. Which choice describes the forces?



Question set: push back to town

Choose from among these responses for the NEXT FOUR QUESTIONS. You may use each response once, more

than once, or not at all.

1 The force exerted by the car pushing against the truck is equal to that exerted by the truck pushing back against

the car.

2 The force exerted by the car pushing against the truck is less than that exerted by the truck pushing back against

the car.

3 The force exerted by the car pushing against the truck is greater than that exerted by the truck pushing back

against the car.

4 The car’s engine is running so it exerts a force as it pushes against the truck, but the truck’s engine isn’t running

so it can’t exert a force back against the car.

5 Neither the car nor the truck exert any force on each other. The truck is pushed forward simply because it is in

the way of the car.

6 None of these descriptions is correct.

A large truck breaks down out on the road and is pushed back to town by a

small compact car.

Q25. The car is pushing on the truck, but not hard enough to make the truck move.

Q26. The car, still pushing the truck, is speeding up to get to cruising speed.

Q27. The car, still pushing the truck, is at cruising speed and continues to travel at the same speed.

Q28. The car, still pushing the truck, is at cruising speed when the truck puts on its brakes and causes the car to

slow.

Q29. Jose pushes a sled across a horizontal plane. Which description of the sled's motion matches the graph below?

1 The sled moves in the positive direction at a

constant velocity.

2 The sled is at rest.

3 The sled moves in the negative direction at a

constant velocity.

4 The sled moves at a constant non-zero

acceleration.

5 The first three answers are all possible.



Q30. Jose pushes a sled across a horizontal plane. Which description of the sled's motion matches this graph?

1 The sled moves in the negative direction at a

constant velocity.

2 The sled moves in the negative direction and

the sled’s speed is increasing at a constant

acceleration.

3 The sled moves in the positive direction and the

sled’s speed is decreasing at a constant

acceleration.

4 The sled moves in the negative direction and

the sled’s speed is decreasing at a constant

acceleration.

5 Both 2 and 3 are possible.

Part II Free response questions

Choose THREE of the following free response questions and address them on your answer sheets. Clearly indicate

which question you are addressing, and make sure you answer every part of the question.

FR1. The Moving Works shipping company can ship containers with a mass of 30,400 kg. In order to transfer the

containers from the ship to the loading dock, the containers are attached to a heavy-duty cable and then lifted

and moved using a crane.

a) The container is being lowered on the loading dock. It is slowing down to a stop as it approaches the dock. Draw

a force diagram and motion diagram for the container.

b) Are your diagrams consistent? Explain.

c) The maximum upward force the cable can exert on any one container is 309,000 N. What is the maximum

acceleration of the container?

FR2. Describe two different experiments that you can perform to determine the maximum coefficient of static

friction between your physics book and the table. List equipment that you will use. Say clearly how you will

know that the two methods give you the same result.

FR3. Examine the following, unlabeled force diagram.

a) Describe a situation that can be represented by the force diagram.

b) Label the forces in the diagram according to the situation you specified.

c) In which direction does the object in your scenario accelerate? Explain.

d) In which direction does the object in your scenario move? Explain.

e) Draw a motion diagram for the scenario you described in part a.


End of exam. Check your work. Breathe deeply.

FR4. You push a 20 kg lawn mower to the right, exerting a 100 N force on it. You push the lawn mower

horizontally. The effective coefficient of kinetic friction between the grass and mower is 0.60. Assume that g =

10 N/kg.

a) Draw a force diagram for the lawn mower.

b) Determine the acceleration of the lawn mower.

c) In which direction does the lawn mower move? How do you know?

FR5. You are pushing a 33-kg TV and a 20-kg Microwave across a very smooth floor, as seen in the picture below.

Assume friction is so small it can be ignored.

a) Draw a force diagram for the TV.

b) Draw a force diagram for the microwave.

c) Calculate the force you need to exert on the TV box in order for both the TV and microwave to accelerate at 1

m/s2.

d) Would it be easier to switch the order of the boxes and push the microwave box in order to accelerate both boxes

at 1 m/s2? Explain.

FR6. Consider the following experiment: An unbalanced force F exerted on a cart of mass m causes it to move at an

acceleration a. For each new scenario below, describe what should happen to the acceleration. Be specific; for

example, the new acceleration should be twice the old acceleration, or the new acceleration should be one-half the

old acceleration.

a) The unbalanced force exerted on the cart decreases to ½F. The mass stays the same at m.

b) The unbalanced force exerted on the cart increases to 3F. The mass stays the same at m.

c) The unbalanced force exerted on the cart stays at F. The mass decreases to 1/3 m.

d) The unbalanced force exerted on the cart stays at F. The mass increases to 3/2 m.

e) The unbalanced force exerted on the cart increases to 4F. The mass increases to 2m.

f) The unbalanced force exerted on the cart increases to 4F. The mass decreases to ¼ m.

FR7. Consider the following situation: A large box containing a new desktop computer is placed in the back of a

pick-up truck. The driver of the truck steps on the gas and the computer box flies backward.

Explain this situation using two different observers, a passenger in the truck and a person standing on the side of the

road. For each observer, include a motion diagram and force diagram. How is each observer able to explain what

happens to the computer box?

FR8. (Extra Credit) You visit a swimming pool with a 3.6 m long waterslide that is inclined at 30 degrees below the

horizontal plane. You decide to test Newton’s second law by predicting the time interval it will take you to move

down the slide starting at rest. Using a stopwatch you find the time interval is 1.0 ± 0.05 s. Have you managed to

disprove Newton’s second law? Explain your reasoning.

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HS Dynamics Test 2010