# PFC2 Chapter 5 Section 3 Guided Reading

Mechanics

Nov 14, 2013 (4 years and 7 months ago)

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PFC2 Chapter 5 Section 3

1.

_______________
is a force that results from relative motion between objects. It
_______________the motion of objects or surfaces.

2.

_______________ _______________ is

the resistance created when two surfaces slide
across one another.

3.

_______________ _______________ is a type of friction that keeps two surfaces from
sliding across each other.

4.

What causes friction between two smooth, dry surfaces such as a cardboard box
and a
wooden table?

5.

The force of friction acting on a surface always points _______________ to the direction
of motion of that surface.

6.

Static friction acts to keep an object at rest from _______________ _______________
_______________.

7.

Sliding friction is

a force that resists the motion of an object that is _______________
_______________.

8.

Equilibrium is created when a box is pushed across the floor at constant speed, because
the force you apply to push the box cancels the resistive force of ______________
_
_______________.

9.

Suppose you have to push a heavy box full of books across your classroom floor. Which
is more difficult
--
to get it moving or to keep it moving? Why?

10.

Look at
F
igure 5.19 on page 119. The same two surfaces are sliding across each other in
both pictures. Why is it more difficult to pull the paper across the table when the brick is
placed on top?

11.

Suppose you triple the weight of a box that you are sliding across the floor. What
happens to the friction force between the box and floor?

12.

A fluid
used to reduce friction between two surfaces is called a _______________.

13.

Ball bearings change _______________ motion into _______________ motion, which
has much less friction.

14.

Explain how a maglev train reduces friction.

15.

Explain in your own words how fric
tion is useful for one of these applications: bicycles,
tire design, nails, or cleated shoes.