Question

When a box is moving it experiences a frictional force of 20n to the left, or toward the mover. What force does the mover need to apply in order to keep the box moving to the right at 1 m/s?

Answer 1

The mover must apply a force of 20 N to the right to match the 20 N frictional force and keep the box moving at a constant speed.

Step-by-step explanation:

To keep the box moving to the right at a constant speed of 1 m/s, the mover must apply a force that is equal and opposite to the frictional force. Since the frictional force is 20 N to the left, the mover must apply a force of 20 N to the right. This scenario is a direct application of Newtons first law of motion, which states that an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Answer 2

If there's a friction force of 20N toward the left, then you need to apply
a force of 20N toward the right, in order to keep the box moving at a
constant speed.

When there's a force pointing to the left and an equal force pointing
to the right, then the forces on the box are "balanced" ... they add up
to zero, and the box has zero acceleration. That means it moves in a
straight line at a constant speed.