question_answer

The force of friction between the surface of a floor and the surface of a box in contact with the floor in 200 N. We wish to move the box on the floor with constant velocity. How much force has to be applied on the box?

Answer:

                                                               The box will move with a constant velocity if no net external force acts on the body. Thus, the effect of force of friction has to be balanced.                                         So a force equal to the force of friction i.e., 200 N but opposite in direction has to be applied on the box to move it with a constant velocity. So the applied force on the box is 200 N.