Download Chapter 05 MF Test

Name: ________________________ Class: ___________________ Date: __________
ID: A
Chapter 05 Multi-format Test
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
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1. Weight is a force from gravity pulling down on any object with mass. _________________________
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2. By compressing a spring, you increase its length. _________________________
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3. The greater the force squeezing 2 surfaces together, the smaller the friction force.
_________________________
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4. Lubrication reduces the friction between machine parts. _________________________
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5. A zero net force causes an acceleration. _________________________
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6. Force is the ability to change motion. _________________________
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7. Tension is a contact force. _________________________
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
8. If you traveled to Mars, your mass would be _________________________ than your mass on Earth.
9. The _________________________ is the English unit of weight equal to about 0.454 kg of mass.
10. A force that resists the motion of objects or surfaces as they move over one another is called
____________________.
11. A diagram shows all the forces acting on an object is a _________________________ diagram.
12. Force is a(n) ____________________ because it has both an amount and a direction.
13. The metric unit of force required for a 1-kg object to accelerate at 1 m/s 2 is the
_________________________.
Short Answer
14. Describe one similarity and one difference between friction and gravity.
15. Explain how the same object could weigh 50 pounds on Earth and 8.3 pounds on the moon.
16. If there were no friction, we could not walk. Explain why friction is necessary for walking.
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Name: ________________________
ID: A
17. What does it mean when the net force on an object is zero?
Problem
18. A toddler weighs 30.0 pounds. If 1.00 newton equals the weight of 0.228 pounds, what is the weight of the
toddler in units of newtons?
19. Two body builders are involved in a weight lifting contest to determine who is the stronger. Ivan lifts 500
pounds. Vladimir lifts 2000 newtons. Who is stronger?
20.
Planet
Mercury
Venus
Earth
Neptune
Jupiter
Gravitational Force
(N/kg)
3.7
8.9
9.8
11.0
23.1
The table above gives the gravitational force (g) for different planets in our solar system.
A 400-kg space probe has a weight of 3,560 N on one of the above planets. On which planet is the space
probe? Show your work.
21. The diagram represents a cart moving at a constant speed to the right. A force of 10 newtons is applied by the
attached spring scale.
a.
b.
What is the size and the direction of the force of friction acting on the cart?
Would the reading on the spring scale be larger or smaller than 10 N to the right if the
cart is accelerated to the right?
22. 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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Name: ________________________
ID: A
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.
23. Calculate the net force on the box shown in Figure 5-1.
24. 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.
25. Calculate the net force on the box shown in Figure 5-2.
26. Is the box shown in Figure 5-2 accelerating? If not, what type of motion does it have?
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Name: ________________________
ID: A
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.
27. Calculate the net force on the box shown in Figure 5-3.
28. Is the box in Figure 5-3 accelerating? If not, what type of motion does it have?
Essay
29. 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.
Other
30. Draw a diagram that shows a 3-N force, a 5-N force, and an 8-N force acting on a single block that is in
equilibrium.
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ID: A
Chapter 05 Multi-format Test
Answer Section
MODIFIED TRUE/FALSE
1. ANS: T
2. ANS: F, decrease
DIF: basic
3. ANS: F
larger
greater
REF: section 5.1
DIF: basic
4. ANS: T
5. ANS: F
unbalanced
nonzero
REF: section 5.2
DIF: basic
6. ANS: T
7. ANS: T
REF: section 5.3
DIF: basic
REF: section 5.1
DIF: basic
REF: section 5.2
DIF: basic
DIF: basic
REF: section 5.1
REF: section 5.1
COMPLETION
8. ANS: equal to
DIF: basic
9. ANS:
pound
lb
REF: section 5.1
DIF: basic
10. ANS: friction
REF: section 5.1
DIF: basic
11. ANS:
free-body
free body
REF: section 5.2
DIF: basic
12. ANS: vector
REF: section 5.3
DIF:
basic
REF: section 5.1
1
ID: A
13. ANS:
newton
N
DIF:
basic
REF: section 5.1
SHORT ANSWER
14. ANS:
Similarity: Friction and gravity are both forces.
Difference: Friction is a contact force and gravity is an at-a-distance force.
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.
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.
DIF: advanced
REF: section 5.2
17. ANS:
The object is in equilibrium and the forces are balanced. The object is not accelerating, but it may be either at
rest or moving at a constant velocity.
DIF:
intermediate
REF: section 5.3
PROBLEM
18. ANS:
weight in newtons =
weight in pounds
30 lb
=
0.228 pounds per newton 0.228 lb/N
weight in newtons = 132 N
DIF: intermediate REF: section 5.1
19. ANS:
Ivan is stronger; 500 pounds is equal to 2240 newtons, which is larger than Vladimir’s 2000 newtons.
500 pounds × 4.48 newtons/pounds = 2240 newtons
DIF:
intermediate
REF: section 5.1
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ID: A
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.
DIF: advanced
REF: section 5.1
21. ANS:
a. 10 newtons to the left.
b. greater than 10 newtons to the right
DIF: advanced
REF: section 5.2
22. 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
DIF: advanced
REF: section 5.3
23. 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.
DIF: intermediate
24. ANS:
No, the box is not accelerating because the net force is zero. It must either be at rest or moving at constant
velocity.
DIF: intermediate REF: section 5.3
25. ANS:
net force = 6 N in the up direction.
The 10 N force pushing toward the right is canceled by the 10 N force pushing to the left. The 3 N force
pulling up is added to the 3 N force pushing up, for a net force of 6 N in the up direction.
DIF: intermediate REF: section 5.3
26. ANS:
The box is accelerating in the up direction.
DIF: intermediate REF: section 5.3
27. 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.
DIF:
intermediate
REF: section 5.3
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ID: A
28. ANS:
The box is accelerating toward the left.
DIF:
intermediate
REF: section 5.3
ESSAY
29. 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.
DIF:
intermediate
REF: section 5.2
intermediate
REF: section 5.3
OTHER
30. ANS:
DIF:
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Chapter 05 Multi-format Test [Answer Strip]
T
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F
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2.
F
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3.
T
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4.
F
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5.
T
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T
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ID: A