A car, moving with a speed of `50 km//hr`, can be stopped by brakes after at least `6 m`. If the same car is moving at a speed of `100 km//hr`, the minimum stopping distance is

Options

A. 6 m
B. 12 m
C. 18 m
D. 24 m

Answer

D

Explanation

Stopping distanc, `d_s = -u^(2)/2a`
where u is the initial speed of the car.
As the stopping distance is proportional to square of the initial velocity. Doubling the initial velocity increases the stopping distance by a factor of 4.