Question

A particle moves along the circumference of a circle with radius 2 m. It completes 5 revolutions in 10 seconds. Calculate its speed.

• A. $4\pi m/s$
• B. $3\pi m/s$
• C. $\pi m/s$
• D. $2\pi m/s$

Answer 1

The correct option is D $2\pi m/s$

Since, it completes 5 revolutions in 10 s, for 1 revolution it requires 2 s.
Time period, $T=2s$
Circumference of circle, $C=2\pi R$

Speed is given by:
$v=\frac{C}{T}$
$v=\frac{2\pi R}{T}$
$v=\frac{2\pi \times 2}{2}=2\pi m/s$