The driver of a car travelling at velocity v | vedclass

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(A) When the driver applies brakes,the car covers a distance $x$ before coming to rest under the effect of the retarding force $F$. By the work-energy

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brake sharply

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(A) When the driver applies brakes,the car covers a distance $x$ before coming to rest under the effect of the retarding force $F$. By the work-energy theorem: $\frac{1}{2} m v^{2} = F x$,which gives $x = \frac{m v^{2}}{2 F}$.When the driver takes a turn,the required centripetal force is provided by the friction force $F$. Thus,$\frac{m v^{2}}{r} = F$,which gives the radius of the turn as $r = \frac{m v^{2}}{F}$.Comparing the two,we see that $x = \frac{r}{2}$.This implies that by using the same retarding (friction) force,the car can be brought to rest in a shorter distance by applying brakes compared to the radius required to turn the car. Therefore,braking is more effective.

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

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