Question

A body of mass 8 kg moves under the influence of a force. The position of the body and time are related as x = 1/2t 2 where x is in meter and t in sec. The work done by the force in the first two seconds is

Answer 1

x=1/2t²
dx/dt=v=-t^-3
dv/dt=a=3t^-4
force =mass*a
work=force*x
work=8*3/(t⁴*2t²)---for t=2s
work=24/(16*2*4)
work=3/16Joule