It is because both of them are attracted towards earth where the heavier body gravity field influence is more in comparision to small. For eg; there are two magnet with less power in besides of huge power or magnetic influence then both of the less power magnet are attracted towards the huge one rather than attracting themselves.
a 10 kg block reaches a point with a velocity of 15 m per second and slides down a rough track my the coefficient of the kinetic energy between the two surface ab and the block iis0.52
