Question

A body of mass 2kg starts from rest and moves with uniform acceleration. It acquires a velocity of 20m/s in 4 seconds. The power exerted on the body in 2 seconds is
(1) 50watts
(2) 100watts
(3) 150watts
(4) 200watts

Answer 1

Answer:

200 watts..

Explanation:

M=2 kg

u= o m/s

v= 20 m/s

t= 4 s

so, acceleration = (v-u)/t

= 20/4

= 5 m/s^2

therefore, force= 2×5=10 N

s= 1/2 at^2

= 1/2×5×16

= 40 m

so, work = force×displacement

= 10×40

= 400 j

therefore, power = work /time

= 400/2

= 200 watt

hope itt helps..

:))

Answer 2

v=20m/s

t=4sec

s=v×t=20×4=80m

m=2kg

work=energy=force×displacement=2×80= 160j

power =w/t=160/2=80watt