Friction 1

Front

Generally speaking, static friction is stronger than kinetic friction.

Back

True

Front

If the object is not moving and then the force applied is 5 N, what will happen?

Back

The block will not move

Answer explanation

If the object isn't moving, static friction holding it in place. We need to pull harder than the maximum strength of static friction in order to make it move.

Front

If the object is not moving and then the force applied is 8 N, what will happen?

Back

The block will move and continue to speed up

Answer explanation

If the object isn't moving, static friction holding it in place. We need to pull harder than the maximum strength of static friction in order to make it move. Once we do that, the object will accelerate because we are pulling harder than the strength of kinetic friction which is now the friction of the situation.

Front

If the object is not moving and then the force applied is 7 N and we continue to pull, what is the net force? Options: 0 N, 1 N to the right, 3 N to the right, 7 N to the right

Back

3 N to the right

Answer explanation

Since our 7 N pull is greater than the max F_s, now we no longer have static friction. Instead we have 4 N of kinetic friction.

7 - 4 = 3 N to the right.

Front

If the object is moving toward the right and then the force applied is 5 N, what will happen?

Back

The block will move and speed up

Answer explanation

5 N is greater than the 4 N of kinetic friction opposing the motion so there is a net force to the right. This will cause the block to speed up to the right.

Front

If the object is moving to the right and then the force applied is 5 N, what is the net force?

Back

1 N to the right

Answer explanation

5 N to the right is being opposed by 4 N to the left so 5 - 4 = 1 N right.

Front

If the object is moving to the right and then the force applied is 4 N, what will happen?

Back

The block will move at a constant velocity

Answer explanation

Since there is 4 N to the right and 4 N to the left from kinetic friction, the balance each other out and there is no net force. No net force means no acceleration which means it will move at a constant velocity.

Front

If the object is moving to the right and then the force applied is 3 N, what will happen? Options: The block will immediately stop moving, The block will move at a constant velocity, The block will move and speed up, The block will move, but slow down

Back

The block will move, but slow down

Answer explanation

3 N to the right is being opposed by 4 N of kinetic friction to the left so 3 - 4 = -1 N. This is a net force of 1 N to the left. This will cause the block to slow down and eventually stop unless something changes.

Front

If the object is moving to the right and then the force applied is 3 N, what is the net force?

Back

1 N to the left

Answer explanation

3 N to the right is being opposed by 4 N of kinetic friction to the left so 3 - 4 = -1 N. This is a net force of 1 N to the left.

Front

Which is a true statement for this situation?

Back

Static friction can be less than 6 N but kinetic friction will only be 4 N

Answer explanation

3 N to the right is being opposed by 4 N of kinetic friction to the left so 3 - 4 = -1 N. This is a net force of 1 N to the left.