Suppose you have to move a heavy crate of weight 875 n by sliding it along a horizontal concrete floor. you push the crate to the right with a horizontal force of magnitude 300 n, but friction prevents the crate from sliding. what is the magnitude fp of the minimum force you need to exert on the crate to make it start sliding along the floor? let the coefficient of static friction ? s between the crate and the floor be 0.56 and that of kinetic friction, ? k, be 0.47.