Physics

Problem

A car of weight

W

is on an inclined road that rises by 100 m over a distance of 1 Km and applies a constant frictional force

\frac{W}{20}

on the car. While moving uphill on the road at a speed of

10 \text{ ms}^{-1}

, the car needs power

P

. If it needs power

\frac{P}{2}

while moving downhill at speed

v

then value of

v

is: a.

20 \text{ ms}^{-1}

5 \text{ ms}^{-1}

15 \text{ ms}^{-1}

10 \text{ ms}^{-1}