Question

If a particle revolves in a circle of radius $R$, with time period $T$. The average speed and average velocity during two complete revolutions of the particle will respectively be

• A. $\frac{\pi R}{T},0$
• B. $\frac{4\pi R}{T},\frac{\pi R}{T}$
• C. $\frac{2\pi R}{T},0$
• D. $0,\frac{2\pi R}{T}$

Answer 1

The correct option is C $\frac{2\pi R}{T},0$

In two complete cycle, net distance covered will be $2\times 2\pi R=4\pi R$ and net displacement will be zero.
Thus, average speed $v_{\text{av}}=\frac{4\pi R}{2T}=\frac{2\pi R}{T}$ and
average velocity is $\frac{0}{T}=0$