A 20-kg box is at rest on a rough inclined surface of 15 degrees, where the coefficient of static and kinetic friction is 0.35 and 0.25 respectively. (a) Will the box remain stationary? (b) A force of 150 N is applied up the incline? Will the box subsequently start to move, if so with what acceleration)? (c) A force of 125 N is applied down the incline? Will the box subsequently start to move, if so with what acceleration)? (d) What force must be applied to the box to achieve an acceleration of 5 m/s^2 up the incline?