Ncert Exercises & Solutions

For a particle performing uniform circular motion,

(a)	the magnitude of particle velocity (speed) remains constant.
(b)	particle velocity is always perpendicular to the radius vector.
(c)	the direction of acceleration keeps changing as the particle moves.
(d)	angular momentum is constant in magnitude but direction keeps changing.

Choose the correct statement/s:

1.	(c), (d)	2.	(a), (c)
3.	(b), (c)	4.	(a), (b), (c)

(4) Hint: Recall the concept of uniform circular motion.

Step 1: Recall the characteristics of the uniform circular motion.

For a particle performing uniform circular motion

(i) speed will be constant throughout.

(ii) velocity will be tangential in the direction of motion at a particular point.

(iii) acceleration $a = \frac{v^{2}}{r}$ , will always be towards the center of the circular path.

(iv) angular momentum (mvr) is constant in magnitude and direction/out of the plane perpendicularly, as well.