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 arrangement shown in the figure,the pulleys are massless and frictionless,and the threads are inextensible. The block of mass $m_1$ will remain at rest,if

The system of two masses $2 \ kg$ and $3 \ kg$ as shown in the figure is released from rest. The work done on the $3 \ kg$ block by the force of gravity during the first $2 \ s$ of its motion is $\left(g=10 \ m/s^2\right)$. (in $J$)

Two masses of $1\, kg$ and $5\, kg$ are attached to the ends of a massless string passing over a pulley of negligible weight. The pulley itself is attached to a light spring balance as shown in the figure. When the masses are released and start moving,the reading of the spring balance will be:

In the figure,the mass of a ball is $\frac{9}{5}$ times the mass of the rod. The length of the rod is $1 \, m$. The initial level of the ball is the same as the lower end of the rod. Find the time taken by the ball to reach the upper end of the rod. (in $s$)

In the system shown in the figure,the acceleration of the $1\,kg$ mass and the tension in the string connecting between $A$ and $B$ is