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Name: ________________________ Class: ___________________ Date: __________
ID: B
Chapter 05 Test B
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____
1. Force is the ability to change motion. _________________________
____
2. Weight is a force due to gravity pulling on any object with mass. _________________________
____
3. Tension is a contact force. _________________________
____
4. By compressing a spring, you increase its length. _________________________
____
5. If an object is at rest, the net force on it must be unbalanced. _________________________
Completion
Complete each statement.
Select the correct term to complete each sentence. There are extra terms in the list.
greater than
vector
tension
newton
net
less than
scalar
compression
pound
equilibrium
equal to
friction
normal
kilogram
free-body
6. If you traveled to Mars, your mass would be _________________________ than your mass on Earth.
7. Force is a(n) ____________________ because it has both an amount and a direction.
8. The _________________________ is the English unit of weight equal to about 0.454 kg of mass.
9. The SI unit of force required for a 1-kg object to accelerate at 1 m/s 2 is the _________________________.
10. A force that resists the motion of objects or surfaces as they move over one another is called
____________________.
11. The force exerted by a surface on an object that is pressing on it is the ____________________ force.
12. The force which is the sum of all forces acting on a object is called ____________________ force.
13. A diagram shows all the forces acting on an object is a _________________________ diagram.
Short Answer
An astronaut brings her lucky horseshoe on a mission to the Moon. Answer the following questions about this
horseshoe.
14. Would the lucky horseshoe’s mass on the Moon be the same, greater than, or less than the mass of the
horseshoe when it is on the Earth? Explain your answer.
15. Explain how the same object could weigh 50 pounds on Earth and 8.3 pounds on the Moon.
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16. If there were no friction, we could not walk. Explain why friction is necessary for walking.
17. Why does it take longer for a skidding car to stop on an icy road than on a dry road?
18. What does it mean when the net force on an object is zero?
Problem
19. According to legend, Galileo dropped two balls from the Tower of Pisa to see which would fall faster.
Suppose one of the balls had a mass of 5.0 kilograms. Given the acceleration of gravity is 9.8 m/s 2, what was
the weight of the ball in newtons?
The table below gives the gravitational force for different planets in our solar system.
Planet
Mercury
Venus
Earth
Neptune
Jupiter
Gravitational Force
(N/kg)
3.7
8.9
9.8
11.0
23.1
20. A 400-kg space probe has a weight of 3,560 N on one of the above planets. According to the table above, on
which planet is the space probe? Show your work.
21. The diagram below represents an object moving to the right with a constant velocity.
What is the value of force F?
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Figure 5-1
This box is being acted upon by forces in the up, down, left, and right directions. Use this diagram to answer
the following questions.
22. Calculate the net force on the box shown in Figure 5-1.
23. Is the box Figure 5-1 accelerating? If not, what type of motion does it have?
Figure 5-2
This box is being acted upon by forces in the up, down, left, and right directions. Use this diagram to answer
the following questions.
24. Is the box shown in Figure 5-2 accelerating? If not, what type of motion does it have?
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Figure 5-3
This box is being acted upon by forces in the up, down, left, and right directions. Use this diagram to answer
the following questions.
25. Calculate the net force on the box shown in Figure 5-3.
26. Is the box in Figure 5-3 accelerating? If not, what type of motion does it have?
Essay
27. When trying to slide an object, it is generally easier to keep the object moving than it is to start the object
moving. Explain why this is so including the terms static and sliding friction in your explanation.
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ID: B
Chapter 05 Test B
Answer Section
MODIFIED TRUE/FALSE
1. ANS:
REF:
2. ANS:
REF:
3. ANS:
REF:
4. ANS:
T
section 5.1
T
section 5.1
T
section 5.1
F, decrease
PTS: 1
DIF: basic
PTS: 1
DIF: basic
PTS: 1
DIF: basic
PTS: 1
5. ANS: F
balanced
zero
DIF: basic
REF: section 5.1
PTS: 1
DIF: basic
REF: section 5.3
PTS: 1
7. ANS: vector
DIF: basic
REF: section 5.1
PTS: 1
8. ANS:
pound
lb
DIF: basic
REF: section 5.1
PTS: 1
9. ANS:
newton
N
DIF: basic
REF: section 5.1
PTS: 1
10. ANS: friction
DIF: basic
REF: section 5.1
PTS: 1
11. ANS: normal
DIF: basic
REF: section 5.2
PTS: 1
12. ANS: net
DIF: basic
REF: section 5.3
DIF: basic
REF: section 5.3
COMPLETION
6. ANS: equal to
PTS: 1
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13. ANS:
free-body
free body
PTS: 1
DIF: basic
REF: section 5.3
SHORT ANSWER
14. ANS:
The mass of the horseshoe would be the same. Mass is a measure of the amount of matter in an object, and the
amount of matter in the horseshoe does not change when it is taken from one place to another.
PTS: 1
DIF: intermediate REF: section 5.1
15. ANS:
Weight depends on gravity. The strength of gravity depends on the size of the planet. The Moon is much
smaller than the Earth, and its gravity is only 1/6 as strong.
PTS: 1
DIF: intermediate REF: section 5.1
16. ANS:
When you walk, your feet push backwards against the ground. Friction keeps your feet from slipping and
allows the force of the ground on your feet to move you forward. Without friction, your foot could not exert
any backwards force on the ground, and your foot would just slip.
PTS: 1
DIF: advanced
REF: section 5.2
17. ANS:
The ice reduces the friction between the tire and the road.
PTS: 1
DIF: advanced
REF: section 5.2
18. ANS:
The object is in equilibrium and the forces are balanced. The object is not accelerating. it may be either at rest
or moving at a constant velocity.
PTS: 1
DIF: intermediate
REF: section 5.3
PROBLEM
19. ANS:
weight in newtons = mass × acceleration of gravity
weight in newtons = 5.0 kilograms × 9.8 m/s2
weight in newtons = 49 newtons
PTS: 1
DIF: intermediate
REF: section 5.1
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20. ANS:
Venus
weight 3560 N
g=
=
= 8.9 N/kg
mass
400 kg
The planet with a gravitational force of 8.9 kg/N is Venus.
PTS: 1
DIF: advanced
REF: section 5.1
21. ANS:
In order for the box to move at a constant velocity, it must be in equilibrium with a net force of zero.
Therefore, the force F pulling to the left must balance the 6 N force pulling to the right.
F=6N
PTS: 1
DIF: advanced
REF: section 5.3
22. ANS:
The net force is zero. All the forces cancel out: There are 10 N pushing to the right and 10 N pushing to the
left. There are 6 N pushing up and 6 N pushing down.
PTS: 1
DIF: intermediate
23. ANS:
No, the box is not accelerating because the net force is zero. It must either be at rest or moving at constant
velocity.
PTS: 1
DIF: intermediate REF: section 5.3
24. ANS:
The box is accelerating to the right direction.
PTS: 1
DIF: intermediate REF: section 5.3
25. ANS:
net force = 10 N toward the left
The 5 N force pulling up is canceled by the 5 N force pulling down. The 5 N force pulling to the left is added
to the 5 N force pushing from the right, for a net force of 10 N to the left.
PTS: 1
DIF: intermediate
26. ANS:
The box is accelerating toward the left.
PTS: 1
DIF: intermediate
REF: section 5.3
REF: section 5.3
ESSAY
27. ANS:
To start an object moving, static friction force must be overcome. To keep an object moving, sliding friction
force must be overcome. For a given object, the value for the static friction force is greater than the sliding
friction force.
PTS: 1
DIF: intermediate
REF: section 5.2
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Chapter 05 Test B [Answer Strip]
T
_____
1.
T
_____
2.
T
_____
3.
F
_____
4.
F
_____
5.
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ID: B