a ball at point A has a vel=2m/s & at point B has a kinetic energy of 7.5J. what is its KE at A and its v at B

Answer 1

The only way this can be solved is to assume that the ball is not accelerated between A and B. Thus v at B = v at A, and KE at A = KE at B. What you can deduce from this data is the ball's mass.
KE/v = 0.5mv^2/v = 0.5mv = 7.5/2
m = 3.75