A car of mass `m`, travelling at speed `v`, stops in time `t` when maximum braking force is applied. Assuming the breaking force is same for both cases, what time would be required to stop a car of mass `2 m` travelling at speed `v` ?

Options

A. `(1)/(2) t`
B. `t`
C. `sqrt(2) t`
D. `2 t`

Answer

D

Explanation

Let the acceleration of first car be `a`. Then acceleration of second car is.
For first car, `0 = v - at` or `t = (v)/(a)`
For second car, `0 = v - (a)/(2) t'` or `t' = (2v)/(a) = 2t`.