Five identical balls each of mass $m$ are placed adjacent to each other at rest on a smooth horizontal floor. An another identical ball moving with speed $v$ collides elastically with the left most ball as shown in figure. After collision(s)

A bob of mass $\mathrm{m}$ is pulled along a circular arc by means of a constant horizontal force $P$ as shown. Work done by the force $P$ while lifting the bob from $A$ to $B$ is

A particle of mass $0.1 \mathrm{kg}$ is subjected to a force which varies with distance as shown in figure. If it starts its journey from rest at $x=0 \mathrm{m},$ its velocity at $x=12 \mathrm{m}$ is