Select the correct statement regarding pseudo force.

$A$ simple pendulum is attached to a block which slides without friction down an inclined plane $ABC$ having an angle of inclination $\alpha$ as shown below. While the block is sliding down,the pendulum oscillates in such a way that at its mean position,the direction of the string is

$A$ body of mass $1.0 \, kg$ is falling with an acceleration of $10 \, m/s^2$. Its apparent weight will be ......... $kg \, wt$ $(g = 10 \, m/s^2)$.

$A$ weight is suspended from the ceiling of a lift by a spring balance. When the lift is stationary,the spring balance reads $W$. If the lift suddenly falls freely under gravity,the reading on the spring balance will be

$A$ body of mass $50 \ kg$ is suspended using a spring balance inside a lift at rest. If the lift starts falling freely,the reading of the spring balance is:

$A$ block of mass $m$ is kept in an elevator which starts moving downward with an acceleration $a$ as shown in the figure. The block is observed by two observers $A$ and $B$ for a time interval $t_0$. The observer $B$ is on the ground (inertial frame). What is the work done by the pseudo force on the block as observed by observer $B$?