In the figure, blocks $A$ and $B$ of masses $2m$ and $m$ are connected with a string and system is hanged vertically with the help of a spring. Spring has negligible mass. Find out magnitude of acceleration of masses $2m$ and $m$ just after the instant when the string is cut

Two fixed frictionless inclined planes making an angle $30^o $ and $60^o $ with the vertical are shown in the figure. Two blocks $A$ and $B$ are placed on the two planes. What is the relative vertical acceleration of $A$ with respect to $B$?

When body is at rest or it is in uniform motion, no force act on it.

Define impulse of force. Time derivative of momentum gives which physical quantity ?

One end of a string of length $l$ is connected to a particle of mass $m$ and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed $v$ the net force on the particle (directed towards the centre) is :

$(i) \;T,$ $(ii)\; T-\frac{m v^{2}}{l},$ $(iii)\;T+\frac{m v^{2}}{l},$ $(iv) \;0$

$T$ is the tension in the string. [Choose the correct alternative].