$A$ car travels north with a uniform velocity. It goes over a piece of mud which sticks to the tyre. The particles of the mud,as they leave the ground,are thrown:

If the position vector of a particle is $\vec{r} = -\cos t \hat{i} + \sin t \hat{j} - 18t \hat{k}$,then what is the magnitude of its acceleration?

$A$ person is standing on an open car moving with a constant velocity of $30\,m/s$ on a straight horizontal road. The man throws a ball in the vertically upward direction and it returns to the person after the car has moved $240\,m$. Find the speed and the angle of projection.

$A$ stone of mass $m$ is tied to a string of length $l$ and rotated in a circle with a constant speed $v$. If the string is released,the stone flies:

$A$ particle is moving in a circular path. The acceleration and momentum vectors at an instant of time are $\vec{a} = 2 \hat{i} + 3 \hat{j} \ m/s^2$ and $\vec{p} = 6 \hat{i} + 4 \hat{j} \ kg \cdot m/s$. Then the motion of the particle is

$A$ body is revolving with a constant speed along a circle. If its direction of motion is reversed but the speed remains the same,then which of the following statements is true?