Question

A particle is moving with constant speed $V$ in a circle of radius $r$. The average acceleration vector (taken over a full circle) is

• A. a constant vector of magnitude $\frac{V^2}{r}$
• B. a null vector.
• C. a vector of magnitude $\frac{V^2}{r}$ directed normal to the plane of the given uniform circular motion.
• D. equal to the instantaneous acceleration vector.

Answer 1

The correct option is B a null vector.

In case of uniform circular motion of a particle, direction of acceleration vector changes from point to point, but magnitude remains same. Now, vector sum of vectors having same magnitude and distributed in all possible directions is zero. Hence, the average acceleration vector taken over a full circle is a null vector.