A satellite is revolving round the earth with orbital speed v0. If it stops suddenly, the speed with which it will strike the surface of earth would be  (ve = escape velocity of a particle from the earth’s surface)

if orbital velocity is v0 kinetic energy is 12mv02  and potential energy -mv02  when it is stopped it has only potential energywhen it hit the surface of the earth potential energy becomes -GMmR= -mgR= -12mve2 loss in potential energy = kinetic energy 12mve2 -mvo2=12mv2    v=ve2-2v02