Question

A car of mass 2000 kg is to be stopped from a speed of 72kmph. If the coefficient of friction between tyres and road is 0.4, then distance travelled before coming to rest is:

($g=10m/s^2$)

• A. 25 m
• B. 50 m
• C. 75 m
• D. 100 m

Answer 1

Answer: (B)

50 m

Velocity of car is $u=72km/hr=20m/s$

Now loss in KE will be equal to work done against friction

So $\mu mgs=\frac{m{v}^2}{2}\Rightarrow s=200/4=50m$