Question

A car moving with a speed of 50 km h^-1 can be stopped by brakers after at least 6 m. If the same car is moving at a speed of 100 km h^-1 the minimum stopping distance is

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

Answer 1

Answer: (D)

24 m

Answer 2

Stopping distance, $d _ { 2 } = - \frac { u ^ { 2 } } { 2 a }$

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.