If force F is constant, then power can also be P=Fv where v is the velocity, which sort of can be derived from P=W/t=Fs/t=Fv. Since F=ma, also P=mav..........(1)

However, if work done is turned into kinetic energy, E=(1/2)mv^2, then P=E/t=(1/2)(mv^2)/t. If that's the case, then v/t=a gives P=(1/2)mav.........(2)

So why is that (1) and (2) not the same?