A girl was playing with her blocks and some massless string. She connected the first block with mass M1 on one end of the string, put the string over
a frictionless pulley, and attached the other block with M2 on the other end of the string. Derive an expression describing the acceleration of each block.
if M1>M2 then acceln is (M1 - M2)g/M1+ M2 and converse if M2> M1