Rocket & Resultant Forces

[pluke100]

Guys got this question and couldn't do it.

The Saturn V rockets which launched the Apollo space missions had the following specifications:(look at attached pic)


Caulculate i) the force(thrust) produced at lift
ii) the resultant force acting on the rocket at lift-off

[Mindscrape]

Looks like you should use conservation of momentum and newton's laws. What did you do?

Also, the problem is a little vague, maybe you could clear it up a little.

[pluke100]

i haven't got an idea what to do with that :S

[OlderDan]

i haven't got an idea what to do with that :S
Change in momentum is the impulse, which for a constant force is the product of force times the duration of the force. Find the change in momentum of the gas ejected by the rocket in some small time interval Δt and go from there.