A rocket moves upward, starting from rest with an acceleration of 31.0 m/s2 for 8.00 s. It runs out of fuel at

Question

A rocket moves upward, starting from rest with an acceleration of 31.0 m/s2 for 8.00 s. It runs out of fuel at the end of the 8.00 s but does not stop. How high does it rise above the ground?

Answer 1

At the end of 8 seconds it is
y=(1/2)at²=(1/2)*31*8² = 992 m high and travelling at
v=at=31*8=248 m/s. When it reaches the top of it's flight, its velocity is 0 and it has travelled another
v²/2g = 248²/2*9.8 = 3138 m for a total height of
3138 + 992 = 4130 meters

Doug

Answer 2

992 m