when the box is moving ,it experiences a friction force of 20 N to the left , or toward the mover . what force does the mover need to applying order to keep the box moving to the right at 1 m/s?
Force = mass * acceleration
F = ma
Force = 20 Newtons
Mass = ?
Acceleration = 1 m/s
Here, we don't need to find the mass. Which is why this is such a tricky question.
Instead, we need to find the force.
Of course, we know already that force doesn't necessarily require a direction.
F = 20 N
The force needed would be 20 Newtons, as said.