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

Options

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

Answer

C

Explanation

Initial speed of the car u = 50 km/h =` (500)/(36)`m/s
Final speed `nu=0`
Using equation of motion `nu^(2)-u^(2)=2as`
`a=-(u^(2))/(2s)=-(1)/(2)((500)/(36))^(2)xx(1)/(2)=-16m//s^(2)`
If `u = 100 km//h=2xx(500)/(36) ` m/s = 27.78 m/s
`s= (u^(2))/(2a)= ((27.78)^(2))/(2xx16) = 24m.`