$A$ particle is kept at rest at the top of a sphere of diameter $42\, m$. When disturbed slightly,it slides down. At what height $H$ from the bottom will the particle leave the sphere? $(...\, m)$

$A$ mass $m$ is attached to a string and revolves in a vertical circle. What is the tension in the string when the mass is at the lowest position?

$A$ stone is tied to a string of length $L$ and is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time, the stone is at its lowest position and has a speed $u$. The magnitude of the change in its velocity as it reaches a position where the string is horizontal is

$A$ small cube with mass $M$ starts at rest at point $1$ at a height $4R$,where $R$ is the radius of the circular part of the track. The cube slides down the frictionless track and around the loop. The force that the track exerts on the cube at point $2$ is nearly ......... times the cube's weight $mg$.

$A$ $1 \,kg$ stone at the end of a $1 \,m$ long string is whirled in a vertical circle at a constant speed of $4 \,m/s$. The tension in the string is $6 \,N$ when the stone is at:

$A$ bucket filled with water is tied to a string of length $1.6 \, m$ and rotated in a vertical circle. What should be the minimum velocity at the highest point so that the water does not spill? $(g = 10 \, m/s^2)$