### Friction-Section

```Friction Section
Review
1. What is Friction?
 A.
a force creating motion
 B. a force of motion
 C. a force opposing motion
 D. velocity
 C.
A force opposing motion
2. What are two factors that
determine the amount of
friction?
 A.
the force and roughness of the
surfaces
 B. hills and valleys and the roughness of
the surfaces
 C. the force and how much surface
comes n contact
 D. the force and weight exerted on the
surfaces.
 A.
the force and roughness of the
surfaces.
3. What kind of friction takes
place between moving
surfaces?
 a.



kinetic
b. static
c. smooth
d. rough
 A.
Kinetic
4. What type of kinetic friction
is used to write with a pencil?
 a.



static
b. sliding
c. rolling
d. smooth
 B.
sliding
5. Which of these is opposed
by kinetic friction?
 A.
a book sitting on a table
 B. a cat standing in the yard
 C. a child leaning on a building
 D. a box sliding on the floor.
 D.
a box sliding on the floor. Kinetic friction
occurs when two objects are moving in
opposite directions of each other.
6.Use the figure to help answer the question: Look
at Figure A below. Why does the block not move?
 a.
no force applied
 b. force of friction
 c. surface friction
 d. kinetic friction
 A.
No force is applied
7. Use the figure to help answer the question: Look at
Figure B below. 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
 C.
static friction
8. In which of the following
 A.
soil erosion
 B. car tires moving a car forward
 C. engine parts wearing out
 D. holes developing in your socks
 B.
car tires moving your car forward.
9. 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.
 A.
you would slip and fall
10. How do lubricants affect
friction?
 a.
increases friction
 b. decreases friction
 c. increases force
 d. decreases force
 B.
decrease friction
11. How does sand on an icy
 a.
It makes surfaces hotter
 B. it makes surfaces smoother
 C. it makes surface rougher
 D. it makes surfaces nicer
 C.
it makes surfaces rougher
12. Which of these is opposed
by static friction?
 A.
a chair sliding on the floor
 B. a pencil rolling on the table
 C. a dog running in the yard
 D. a worker pushing a non moving box
 D.
a worker pushing a non-moving box
13. Why is it easy to slip when
there is water on the floor?
 A.
the water is very wet
 B. the water creates static friction
 C. the water acts as a lubricant
 D. the water creates hills and valleys on
the floor
 C.
the water acts as a lubricant
14. In which of the following is
friction harmful?
 A.
brakes stopping a car
 B. an eraser erasing
 C. car engine parts wearing out
 D. a person walking
 C.
car engine parts wearing out.
15. Which would NOT be a
way to reduce friction?
 A.
pouring sand on ice
 B. lubricating with oil
 C. using sandpaper
 D. using ball bearings
 A.
pouring sand on ice.
16. What would be the benefit
of using snow tires on a car?
 A.
they reduce the amount of friction
 B. they’re for snow……….duh
 C. they increase friction
 D. they create rolling kinetic friction
 C.
they increase friction
17. What is one way to
increase friction when sanding
a piece of wood?
 a.
Press harder.
 b. Freeze the wood.
 c. Use oil.
 d. Use ball bearings.