Question

What is the smallest radius of a circle at which a bicyclist can travel, if his speed is $7$ $m/s$, coefficient of static friction between the tyres and the road being $0.25$?

[Assume g=$10m/s^2$]

• A. $10$ $m$
• B. $20$ $m$
• C. $5$ $m$
• D. $15$ $m$

Answer 1

The correct option is B $20$ $m$

Centripetal force = Frictional force
$\Rightarrow$ $\frac{m{v}^2}{r}=\mu mg$
$\therefore r=\frac{v^2}{\mu g}$
$\therefore r=\frac{7^2}{0.25\times 10}$
$\therefore r=19.6m\approx 20m$