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 126 N at an angle of 27.0° 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.
(a) Find the acceleration of the box.
(b) The student now starts moving the box up a 10.0° incline, keeping her 126 N force directed at 27.0° above the line of the incline. If the coefficient of friction is unchanged, what is the new acceleration of the box?