CP Workbook Newton's Law of Motion: Friction
Refer to the following information for the next two questions.

A crate filled with delicious junk food rests on a horizontal floor. Only gravity and the support force of the floor act on it, as shown by the vectors for weight W and normal force N.

The net force on the crate is
 Evidence for this is ____.

Refer to the following information for the next three questions.

A slight pull P is exerted on the crate, not enough to move it.

A force of friction f now acts, which is ____ P.
This type of friction is called ____ friction.
The net force on the crate is
Refer to the following information for the next four questions.

The pull on the crate is increased until the crate begins to move. It is pulled with pull P so that it moves with constant velocity across the floor.

Friction f is ____ P.
This type of friction is called ____ friction.
Constant velocitv means acceleration is
The net force on the crate is ____ zero.
Refer to the following information for the next two questions.

Pull P is further increased and is now greater than friction f.

The net force on the crate is ____ zero.
The net force acts toward the right, so acceleration acts toward the

Summary Questions

 If the pulling force P is 150 N and the crate doesn't move, what is the magnitude of the static friction, f?

 If the pulling force P is 200 N and the crate doesn't move, what is the magnitude of the static friction, f?

 If the force of sliding friction is 250 N, what force is necessary to keep the crate sliding at constant velocity?

 If the mass of the crate is 50 kg and sliding friction is 250 N, what is the acceleration of the crate when the pulling force is 250 N?

 If the mass of the crate is 50 kg and sliding friction is 250 N, what is the acceleration of the crate when the pulling force is 300 N?

 If the mass of the crate is 50 kg and sliding friction is 250 N, what is the acceleration of the crate when the pulling force is 500 N?