A bob of mass $m$, suspended by a string of length $I_1$, is given a minimum velocity required to complete a full circle in the vertical plane, At the highest point, it collides elastically with another bob of mass $m$ suspended by a string of length $I_2$, which is initially at rest. Both the strings are mass-less and inextensible. If the second bob, after collision acquires the minimum speed required to complete a full circle in the vertical plane, the ratio $\frac{I_1}{I_2}$ is :

In an inelastic collision, what is conserved

A particle of mass $m$ is moving with speed $2\, v$ collides with a mass $2\,m$ moving with speed $v$ in the same direction. After collision, the first mass is stopped completely while the second one splits into two particles each of mass $m$, which move at angle $45^o$ with respect to the original direction. The speed of each of the moving particle will be

In figure, determine the type of the collision The masses of the blocks, and the velocities before and after the collision are given. The collision is

Three particles $A, B$ & $C$ of equal mass move with speed $V$ as shown to strike at  centroid of equilateral triangle after collision. $A$ comes to rest & $B$ retraces its path  with speed $V$. speed of $C$ after collision is :-

An unknown nucleus collides with a ${}^4He$ nucleus, and after the collision the two nuclei travel in perpendicular directions relative to each other. If kinetic energy is lost in the collision, the unknown nucleus must be