Question

A car starts from rest. It has to come to rest after covering distance of 500 m. The coefficient of friction between the road and the tyre is 1/2. The minimum time in which the car can cover this distance is (g=10 $m/s^2$)

• A. 20 s
• B. 10 s
• C. 30 s
• D. 15 s

Answer 1

The correct option is B 10 s

The friction of force$=\mu$mg.

$g=10$

$f=0.5\times 10=5$

$s=ut+\frac{1}{2}g{t}^2$

$500=0.5\times 10\times t^2$

$t^2=100$

$\Rightarrow t=\sqrt{100}=10$sec.