Friction: a Force That Opposes Motion
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Skills Worksheet
Friction: A force that opposes motion
Section: Friction: A Force That Opposes Motion
Circle the letter of the best answer for each question.
1.What unbalanced force causes a ball to stop rolling?
a. friction
b. gravity
c. thrust
d. push
The Source of Friction
2.What is caused when the hills and valleys of two surfaces meet?
a. balanced force
b. velocity
c. gravity
d. friction
The Effect of Force on Friction
3.Why does sliding a large book take more force than sliding a small book?
a. Large books are rougher.
b. Large books weigh more.
c. Small books are rougher.
d. Small books weigh more.
The Effect of Rougher Surfaces on Friction
4.Which surfaces have more hills and valleys?
a. old surfaces
b. new surfaces
c. smooth surfaces
d. rough surfaces
Directed Reading B continued
Circle the letter of the best answer for each question.
5.Why does dry pavement create more friction than ice does?
a. Ice is rougher.
b. Ice is colder.
c. Dry pavement is smoother.
d. Dry pavement is rougher.
Types of Friction
Kinetic Friction
6.What kind of friction takes place between moving surfaces?
a. kinetic
b. static
c. smooth
d. rough
7.What type of kinetic friction is used to write with a pencil?
a. static
b. sliding
c. rolling
d. smooth
8.What type of kinetic friction is used to roll in-line skates?
a. static
b. sliding
c. rolling
d. smooth
Directed Reading B continued
Static Friction
Circle the letter of the best answer for each question.
9.What kind of friction is happening when force can’t make something move?
a. static
b. kinetic
c. sliding
d. rolling
10.What happens to static friction as soon as an object starts moving?
a. It increases.
b. It decreases.
c. It disappears.
d. It stays the same.
Directed Reading B continued
Use the figures below to answer questions 11, 12, and 13. Circle the letterof the best answer for each question.
11.Look at Figure A above. Why does the block not move?
a. no force applied
b. force of friction
c. surface friction
d. kinetic friction
12.Look at Figure B above. The block does not move. What force keeps the block from moving?
a. rolling kinetic friction
b. sliding kinetic friction
c. static friction
d. kinetic friction
13.Look at the Figure C above. The block is moving. What force acts against the block’s motion?
a. static friction
b. sliding kinetic friction
c. rolling kinetic friction
d. gravity
Friction: Harmful and Helpful
14.What is one way friction is used in a car?
a. to help brakes stop the car
b. to tune the car radio
c. to clean the gasoline
d. to fill the tires
Directed Reading B continued
Circle the letter of the best answer for each question.
15.What is one way that friction can hurt plants?
a. Friction causes erosion.
b. Friction causes disease.
c. Friction causes over watering.
d. Friction causes drought.
16.What would happen if you tried to walk without friction?
a. You would slip and fall.
b. You would get lost.
c. You would change direction.
d. You would go slower.
Some Ways to Reduce Friction
17.What does a lubricant do?
a. increases friction
b. decreases friction
c. increases force
d. decreases force
18.What is used to cut down friction between wheels and axles?
a. sandpaper
b. brakes
c. dirt
d. ball bearings
Some Ways to Increase Friction
19.How does sand on an icy road keep cars from skidding?
a. It makes the surface rougher.
b. It makes the surface smoother.
c. It makes the surface hotter.
d. It makes the surface steeper.
Directed Reading B continued
Circle the letter of the best answer for each question.
20.What is one way to increase friction when you sand a piece of wood?
a. Press harder.
b. Freeze the wood.
c. Use oil.
d. Use ball bearings.
Section Review P.133
Friction: A Force That Opposes Motion
Using Key Terms
1.In your own words, write a definition for the term friction.
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Understanding Key Ideas
_____2.Why is it easy to slip when there is water on the floor?
a.The water is a lubricant and reduces the friction between your feet and the floor.
b.The friction between your feet and the floor changes from kinetic to static friction.
c.The water increases the friction between your feet and the floor.
d.The friction between your feet and the floor changes from sliding kinetic friction to rolling kinetic friction.
3.Explain why friction occurs.
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4.How does the roughness of surfaces that are touching affect the friction between the surfaces?
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5.Describe how the amount of force pushing two surfaces together affects friction.
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6.Name two ways in which friction can be increased.
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7.List the two types of friction, and give an example of each.
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Section Review continued
Interpreting Graphics
8.Why do you think the sponge shown below has a layer of plastic bristles attached to it?
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Critical Thinking
9.Applying Concepts Name two ways that friction is harmful and two ways that friction is helpful to you when riding a bicycle.
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10.Making Inferences Describe a situation in which static friction is useful.
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Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and Technology1Matter in Motion