A body of mass 2 kg starts from rest and moves with uniform acceleration. It acquires a velocity 20 m/s in 4 s. The power exerted on the body in 2 s in Watt is

Options

A. 50
B. 100
C. 150
D. 200

Answer

b

Explanation

Acceleration,` a=(v-u)/t=(20-0)/(4)=5m//s`
Force applied, F=ma
` m.5=2xx5=10N`
Velocity after 2 second, v=u+at
`=0+5(2)=10m//s`
Power, P =F.v`=10xx10=100 watts`