# physics

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A rocket has a per-ignition mass of 1100kgs-1 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 -

You must have misspelled and omitted something.

I assume you mean pre-ignition mass, not per-ignition mass, which makes no sense.

If so, what is the pre-ignition 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 -

i haveeee!! ive posted the right question again please look it up again if you have time :(

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