Posted by beavis on .
A rocket has a perignition mass of 1100kgs1 producing a thrust of 10000N. How long after ignition of the fuel will the rocket lift off?
also explain how is it possible for a rocket to accelerate in space.
(i cant work it outt. i know it involves the rocket thrust equation some how, the newtons 2nd law and suvat's..) thank you

physics 
drwls,
You must have misspelled and omitted something.
I assume you mean preignition mass, not perignition mass, which makes no sense.
If so, what is the preignition mass? The number you have provided is a mass flow RATE.
The rocket lifts off then the trust equals the weight. Use the initial mass and the mass flow rate to figure out when that happens. 
physics 
beavis,
i haveeee!! ive posted the right question again please look it up again if you have time :(