You push with a horizontal force of 50.0N against a 24.0N box, pressing it against a rough wall to hold it in place. The coefficients of kinetic and static friction between this box and the wall are 0.300 and 0.600, respectively.
a. what is the friction force of the box?
b. how hard would you have to press for the box to slide down with a uniform speed of 14.5 cm/s?