**1. The problem statement, all variables and given/known data**

Here is the data I have been given;

mass = 3.4*10^6 kg (at lift off)

mass of first stage propellants = 2.0*10^6

propellant consumption rate = 1.4*10^4 kg/s

g = 9.8 m/s/s

Find the thrust of the engines at lift-off.

**2. Relevant equations**

a = T-mg/m

**3. The attempt at a solution**

So mg = (3.4*10^6)*9.8 = 3.332*10^7

m = 3.4*10^6

∴a = T-3.332*10^7/3.4*10^6

I have two unknowns here, I thought there might be a way of finding either acceleration or thrust using mass, propellant mass and propellant consumption?

I have searched through my HSC texts and haven’t been able to find an equation where I can find ‘a’ or ‘T’ without needing one to find the other.

http://ift.tt/1pRraG8