The driver of a car travelling at velocity v suddenly see a broad wall in front of him at a distance d. He should

Options

A. brake sharply
B. turn sharply
C. Both a and b
D. None of these

Answer

A

Explanation

When driver applies brakes and the car covers distance x before coming to rest, under the effect of retarding force F.
Then `(1)/(2)mv^(2)=Fx`
or `x=(mv^(2))/(2F)`
But when he takes turn, then
`(mv^(2))/(r)=F`
`impliesr=(mv^(2))/(F)`
It is clear that `x=(r)/(2)`
ie, by the same retarding force the car can be stopped in a less distance if the driver apply brakes. This retarding force is actually a friction force.