$A$ disc starts from rest and acquires an angular velocity of $240 \ rpm$ in $10 \ s$. The angular acceleration is ...... $rad/s^2$ (assuming it is constant).

The direction of angular acceleration of a body moving in a circle in the plane of the paper is

$A$ clock has a continuously moving second's hand of $0.1\, m$ length. The average acceleration of the tip of the hand (in units of $m\, s^{-2}$) is of the order of

$A$ wheel,initially at rest,is rotated with a uniform angular acceleration. The wheel rotates through an angle ${\theta _1}$ in the first $1 \ s$ and through an additional angle ${\theta _2}$ in the next $1 \ s$. The ratio $\frac{{\theta _2}}{{\theta _1}}$ is

$A$ particle is revolving in a circle of radius $2 \ m$ with angular velocity $\omega = t^2 - 4t + 8 \ rad/s$. The time when the speed of the particle becomes $8 \ m/s$ is ......... $\sec$.

The angular speed of a flywheel moving with uniform angular acceleration changes from $1200\,rpm$ to $3120\,rpm$ in $16\,s$. The angular acceleration in $rad/s^{2}$ is: (in $\pi$)