She pulls with a force of 168 N at an angle of 30.0 above the horizontal.

A student decides to move a box of books into her dormitory room by pulling on a rope attached to the box. She pulls with a force of 168 N at an angle of 30.0° above the horizontal. The box has a mass of 21.0 kg, and the coefficient of kinetic friction between box and floor is 0.300.