The readings shown in two extended spring balances,$S_1$ and $S_2$,are $60\,kg$ and $30\,kg$ respectively. The lift is accelerating upward with an acceleration of $10\,m/s^2$. The mass $m$ is stationary with respect to the lift. Then the mass of the block will be ......... $kg$. (Take $g = 10\,m/s^2$)

$A$ solid sphere of mass $2\, kg$ is resting inside a cube as shown in the figure. The cube is moving with a velocity $\vec v = (5t\,\hat i + 2t\,\hat j)\,m/s$. Here $t$ is the time in seconds. All surfaces are smooth. The sphere is at rest with respect to the cube. Find the total force $N$ exerted by the sphere on the cube. (Take $g = 10\, m/s^2$)

$A$ block of mass $m$ is kept on a wedge of mass $M$,as shown in the figure,such that mass $m$ remains stationary with respect to the wedge. The magnitude of force $P$ is

The apparent weight of a girl of mass $30 \ kg$ when she is in a lift moving vertically upwards with an acceleration of $2 \ m \ s^{-2}$ is (Acceleration due to gravity $= 10 \ m \ s^{-2}$) (in $N$)

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

$A$ man of mass $80\, kg$ is standing in an elevator which is moving with an acceleration of $6\, m/s^2$ in the upward direction. The apparent weight of the man will be ......... $N$ $(g = 10\, m/s^2)$.