Question

A5000kg rocket is set for vertical firing. The exhaust speed is 800m/s. To give an upward acceleration of 20m/s2 the amount of gas ejected per second to supply the needed thrust is

Answer 1

Acceleration = Change in velocity / Time

Change in speed = Final velocity - initial velocity

Change in speed = 800 - 0 = 800 m/s

20 = 800 / t

20t = 800

t = 40 seconds

In 40 seconds 5000 kg is ejected.

How much can be ejected per second is :

5000 / 40 = 125 kg per second