Question

A car rounds an unbanked curve of radius $92\text{m}$ without skidding at a speed of $26{\text{ms}}^{-1}$. The smallest possible coefficient of static friction between the tyres and the road is

• A. $0.75$
• B. $0.60$
• C. $0.45$
• D. $0.30$

Answer 1

The correct option is A $0.75$

Here it is given that, $r=92\text{m},v=26{\text{ms}}^{-1}$.

As we know that the frictional force provides the necessary centripetal force.
$\frac{m{v}^2}{r}=f=\mu N=\mu mg$
$\Rightarrow \mu =\frac{v^2}{rg}$
$\Rightarrow \mu =\frac{26\times 26}{92\times 9.8}=0.75$

Hence option C is the correct answer