$A$ body of mass $2\, kg$ is hung on a spring balance mounted vertically in a lift. If the lift moves up with an acceleration equal to the acceleration due to gravity $g$,the reading on the spring balance will be .......... $kg$.

$A$ person is standing in an elevator. In which of the following situations does he find his weight to be less than his actual weight?

$A$ monkey is sitting on the pan of a spring balance which is placed on an elevator. The maximum reading of the spring balance will be when

$A$ ball is dropped from an elevator moving upward with acceleration '$a$' by a boy standing in it. What is the acceleration of the ball with respect to the boy and the ground respectively? [Take upward direction as positive]

$A$ boy of $50 \, kg$ is in a lift moving down with an acceleration of $9.8 \, m/s^2$. The apparent weight of the boy is ........... $N$ $(g = 9.8 \, m/s^2)$.

Two wooden blocks of masses $M$ and $m$ are placed on a smooth horizontal surface as shown in the figure. If a force $P$ is applied to the system as shown in the figure such that the mass $m$ remains stationary with respect to the block of mass $M$,then the magnitude of the force $P$ is