A 7400 kg rocket blasts off vertically from the launch pad with
a constant upward acceleration of 2.35 m/s2 and feels no
appreciable air resistance. When it has reached a height of 535 m,
its engines suddenly fail so that the only force acting on it is
now gravity. a-How much time after engine failure will elapse
before the rocket comes crashing down to the launch pad b-How
fast will it be moving just before it crashes