00:01
So let's say we have a missile that has an expulsion rate, like a mass expulsion rate of r, which is measured in like kilograms per second or something like that.
00:16
And the rocket, let's say, has a takeoff mass of m.
00:19
We want to know what is the takeoff acceleration of this rocket then.
00:24
So if we think about it, the acceleration or the force on the rocket is going to be the mass time.
00:31
The velocity that the gas is expelled at, which i call it v.
00:36
Actually, let's call it u.
00:38
So it'll be mu, which is like the momentum of this times r.
00:41
And this should be equal to, this should be equal to, sorry, we should call this r times u.
00:49
This should be equal to the mass of the rocket times its acceleration, right? because r is the rate, the mass rate of change.
00:55
We'll call this like dmd or something like that.
00:58
So a, we can see is going to be r times u.
01:02
Over the takeoff mass of the rocket.
01:05
And so for part b, we want to calculate this...