$A$ disc of mass $m$ and radius $r$ is free to rotate about its centre as shown in the figure. $A$ string is wrapped over its rim and a block of mass $m$ is attached to the free end of the string. The system is released from rest. The speed of the block as it descends through a height $h$ is:

What is a rigid body? Explain the difference between a rigid body and a solid body.

$A$ $3.0\ kg$ bobbin consists of a central cylinder of radius $5.0\ cm$ and two end plates each of radius $6.0\ cm$. It is placed on a slotted incline,where friction is sufficient to prevent sliding. $A$ block of mass $4.5\ kg$ is suspended from a cord wound around the bobbin and passing through the slot under the incline. If the bobbin is in static equilibrium,what is the angle of tilt $\theta$ of the incline?

$A$ rod of length $1 \ m$ is held vertically. What will be the speed of the other end when it touches the ground without slipping?

Two particles of equal mass $m$ at $A$ and $B$ are connected by a rigid light rod $AB$ of length $L$ lying on a smooth horizontal table. An impulse $J$ is applied at $A$ in the plane of the table and perpendicular to $AB$. Then the velocity of the particle at $A$ is:

$A$ mass $m$ hangs with the help of a string wrapped around a pulley on a frictionless bearing. The pulley has mass $m$ and radius $R$. Assuming the pulley to be a perfect uniform circular disc,the acceleration of the mass $m$,if the string does not slip on the pulley,is