A single wire $ACB$ passes through a smooth ring at $C$ which revolves at a constant speed in the horizontal circle of radius $r$ as shown in the figure. The speed of revolution is
$\sqrt{rg}$
$\sqrt{2rg}$
$2\sqrt{2rg}$
$2\sqrt{rg}$
The angular velocity of a particle rotating in a circular orbit $100$ times per minute is
Roads are banked on curves so that
A particle of mass $200 \,g$ is moving in a circle of radius $2 \,m$. The particle is just 'looping the loop'. The speed of the particle and the tension in the string at highest point of the circular path are $\left(g=10 \,ms ^{-2}\right)$
The second's hand of a watch has $6\, cm$ length. The speed of its tip and magnitude of difference in velocities of its at any two perpendicular positions will be respectively
A car changes speed from $18\,km/h$ to $36\,km/h$ in $5\,s$. The diameter of its wheel is $0.8\,m$ . The angular acceleration of the wheel is ........ $rad/s^2$