$A$ lift is moving down with an acceleration $a$. $A$ man in the lift drops a ball inside the lift. The acceleration of the ball as observed by the man in the lift and a man standing stationary on the ground are respectively:

$A$ simple pendulum is set up in a trolley which moves to the right with an acceleration $a$ on a horizontal plane. Then the thread of the pendulum in the mean position makes an angle $\theta$ with the vertical.

An object of mass $5\, kg$ is attached to the hook of a spring balance and the balance is suspended vertically from the roof of a lift. The reading of the spring balance when the lift is going up with an acceleration of $0.25\, m/s^2$ is ......... $N$ $(g = 10\, m/s^2)$

If a man of mass $50 \,kg$ is in a lift moving down with an acceleration equal to acceleration due to gravity, then the apparent weight of the man is

$A$ vessel containing water is given a constant acceleration $a$ towards the right,along a straight horizontal path. Which of the following diagrams represents the surface of the liquid?

In the figure,the reading of the spring balance will be $......\,N$ $\left[ g = 10\,m/s^2 \right]$.