In the figure shown the velocity of lift is $2\,m / s$ while string is winding on the motor shaft with velocity $2\,m / s$ and block $A$ is moving downwards with a velocity of $2\,m / s$, then find out the velocity of block $B -$

Two blocks of same mass $(4\ kg)$ are placed according to diagram. Initial velocities of bodies are $4\ m/s$ and $2\ m/s$ and the string is taut. Find the impulse on $4\ kg$ when the string again becomes taut  .......... $N-s$

A balloon of mass $m$ is descending down with an acceleration $\frac{g}{2}$.  How much mass should be removed from it so that it starts moving up with same acceleration?

In the figure shown the velocity of different blocks is shown. The velocity of $C$ is $.........\,m/s$

Three blocks $A, B$ and $C$ are suspended as shown in the figure. Mass of each blocks $A$ and $C$ is $m$. If system is in equilibrium and mass of $B$ is $M$, then :

The pulleys in the diagram are all smooth and light. The acceleration of $A$ is a upwards and the acceleration of $C$ is $f$ downwards. The acceleration of $B$ is