Given $m_1 = 4m_2$. The acceleration of $m_1$ is $a$. The time taken for $m_1$ to reach the ground is ........ $\text{sec}$. (Assume the initial height is $0.2 \text{ m}$)

To paint the side of a building,a painter normally hoists himself up by pulling on the rope $A$ as shown in the figure. The painter and platform together weigh $200 \, N$. The rope $B$ can withstand a maximum tension of $300 \, N$. Then:

One end of a string of length $l$ is connected to a particle of mass $m$ and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed $v$,the net force on the particle (directed towards the centre) is ($T$ is the tension in the string).

In the arrangement shown,the mass $m$ will ascend with an acceleration (Pulley and rope are massless).

Find the mechanical advantage for pulling mass $M$ by the person as shown in the figure.

In the arrangement shown in the figure, the work done by the string on the block of mass $0.36 \,kg$ during the first second after the blocks are released from a state of rest is: (Ignore friction and the mass of the string.)
(Acceleration due to gravity, $g = 10 \,m/s^2$) (in $\,J$)