$A$ particle of mass $m$ is moving in a circular path of constant radius $r$ such that its centripetal acceleration is varying with time as $a_c = k^2rt^2$. The power delivered to the particle by the forces acting on it is $(k = \text{constant})$

$A$ stone is tied to one end of a string $50\, cm$ long and is whirled in a horizontal circle with a constant speed. If the stone makes $10$ revolutions in $20\, s$,what is the magnitude of the acceleration of the stone in $cm/s^2$?

$A$ disc is rotating with constant angular velocity $\omega$ about an axis passing through centre $C$ and perpendicular to the plane of the disc. An insect is moving over the disc along the radial direction with constant velocity $v$ with respect to the disc. The acceleration of the insect at the instant when its distance from the centre is $r$ will be :-

In non-uniform circular motion,the ratio of tangential to radial acceleration is ($r$ is the radius of the circle,$v$ is the speed of the particle,$\alpha$ is the angular acceleration).

$A$ car is moving at a speed of $40\,m/s$ on a circular track of radius $400\,m.$ This speed is increasing at the rate of $3\,m/s^2.$ The acceleration of the car is ........ $m/s^2$.

$A$ car is travelling with linear velocity $v$ on a circular road of radius $r$. If it is increasing its speed at the rate of $a \ m/s^2$,then the resultant acceleration will be