awash

A block slides on a rough 45 degree incline .the coefficient of friction the block and incline is µk. what is the ratio of acceleration when the block accelerates down the incline to the acceleration when the block is projected up the incline?

A stationary mass explodes in to two parts of masses 0.4 Kg and 4 Kg . if the larger mass has a kinetic energy of 100J ,what is the kinetic energy of the small mass ?