A body of mass 2 ~kg starts from rest and moves with uniform acceleration. It acquires a velocity 20 ~ms ⁻¹ in 4 ~s . The power exerted on the body in 2 ~s in watts is

Step-by-step solution

m=2 ~kg , u=0, v=20 ~m / s , t=4 sec Acceleration a= v-u t = 20-0 4 =5 ~m / s ^2 Force applied F=m a=2 5=10 ~N Velocity at the end of 2 sec v=u+a t=0+5 2=10 ~m / s Power P=F v=10 10=100 watt