Question

A painter of mass $M$ stand on a platform of mass $m$ and pulls himself up by two ropes which hang over pulley as shown. He pulls each rope with the force $F$ and moves upward with uniform acceleration '$a$'. Find '$a$' (neglecting the fact that no one could do this for long time and also neglecting air drag and other $frictional$ forces in the pulley)

Answer 1

Draw free body diagram, as

As system move upward with acceleration $a\left(let\right)$.

$4f-(M+m)g=(M+m)a$

$a=\frac{4f-(M+m)g}{M+m}$