Question

A car is moving in the uniform speed of 20m/s. If the frictional force is 500N, what will be the power of the engine?
200 W
1000 W
10000 W
50000 W

Answer 1

Given,

Final velocity, v=0

Initial velocity, u=30ms

−1

Force = mass x acceleration

F=ma

a=F/m=−5000/1000=−5ms

−2

From the First equation of motion,

v=u+at

0=30+(−5t)

0=30−5t

5t=30

t=30/5

t=6

Hence, after6sec car will stop.