Question

A car runs at constant speed on a circular track of radius 100 m taking 62.8 s on each lap. What is the average speed and average velocity on each complete lap? $(\pi =3.14)$

• A. Velocity 10 m/s, speed 10 m/s
• B. Velocity zero, speed 10 m/s
• C. Velocity zero, speed zero
• D. Velocity 10 m/s, speed zero

Answer 1

The correct option is B Velocity zero, speed 10 m/s

Radius of lap = 100m
Circumference $=2\pi R=200\pi =628m$
time taken to cover one lap = 62.8s
Hence average speed $=\frac{628}{62.8}=10m{s}^{-1}$
Average velocity = 0 as the inital and final positions are same (after completing a lap) (displacement = 0)
Hence option B is correct.