A man of mass 60 kg is standing on a weighing machine kept in a box of mass 30 kg as shown in the diagram, If the man manages to keep the box stationary find the reading of the weighing machine.

Explanation

We know that Normal reaction = scale reading
For man `T-Mg+R=M.0`
For box : `T-R-mg=m.0`
`cancel(T)-Mg+R=cancel(T)-R-mg`
`2R=(M-m)g`
`R=((60-30)xx10)/(2)=150 N`