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 $0.2 \text{ m}$)

$A$ block of mass $M$ is hanging over a smooth and light pulley through a light string. The other end of the string is pulled by a constant force $F$. The kinetic energy of the block increases by $20\,J$ in $1\,s$.

As shown in the figure,two equal masses each of $2\, kg$ are suspended from a spring balance. The reading of the spring balance will be ......... $kg$.

In the system shown in the figure,there is no friction anywhere. The block $C$ $(2 \, kg)$ moves down by a distance $x_0 = 10 \, cm$ with respect to the wedge $D$ $(4 \, kg)$ when the system is released from rest. The velocity of $A$ $(1 \, kg)$ with respect to $B$ $(1 \, kg)$ will be $(g = 10 \, m/s^2)$ ......... $m/s$.

In the system shown in the adjoining figure,the tension $T_2$ is

Two masses $M_1$ and $M_2$ are accelerated uniformly on a frictionless surface as shown in the figure. The ratio of the tensions $T_1/T_2$ is: