Forces

Front

Friction is a contact force that acts _______ to the surfaces in contact.

Back

parallel

Front

When an object is moving, friction acts in the _______ direction as the motion.

Back

opposite

Front

The magnitude of the friction force depends on the force pushing the surfaces together.

Back

True

Front

The type of friction that prevents an object from moving is called _______ friction.

Back

static

Front

A type of friction that occurs when air pushes against a moving object to decelerate.

Back

air resistance

Front

How would the absence of friction affect the motion of a marble on a long, straight path?

Back

The marble's speed would remain constant.

Front

Does polishing two surfaces in contact reduce the friction between them?

Back

False

Front

Which of the following is an example of rolling kinetic friction?

• A box sliding across the floor.
• A car skidding to a stop.
• A soccer player making a slide tackle.
• A bike being ridden on a road.

Back

A bike being ridden on a road.

Front

The equation for the force of friction is _______.
Options:

Ff = µF_g

,

Ff = µF_N

,

Ff = µF_T

,

Ff = µF_s

Back

Ff = µF_N

Front

What affect would decreasing the normal force between two objects have on the force of friction?

Back

The force of friction would decrease.