A $$4000$$ kg rocket is fired. If the exhaust speed is $$500$$ ms–$$1$$ , how much gas must be ejected per second to supply the thrust needed, (a) to overcome the weight of the rocket, (b) to give the rocket an initial acceleration of $$9.8$$ ms–$$2$$ ?

Question

A $$4000$$ kg rocket is fired. If the exhaust speed is $$500$$ ms–$$1$$     , how much gas must be ejected per second to supply the  thrust needed,   (a) to overcome the weight of the rocket, (b) to give the rocket an initial acceleration of $$9.8$$ ms–$$2$$     ?

Infinity Learn · Accepted Answer

$$i)$$ $$Mg=udmdt$$                                           $$4000$$×$$9.8=500dmdt$$⇒$$dmdt=8$$×$$9.8=78.4$$       $$ii)$$ $$M(g+a)=udmdt$$                            $$4000(9.8+9.8)=500dmdt$$     $$dmdt=8$$×$$19.6=156.8kgs$$−$$1$$

A 4000 kg rocket is fired. If the exhaust speed is $500 {ms}^{- 1}$ , how much gas must be ejected per second to supply the thrust needed,
(a) to overcome the weight of the rocket,

(b) to give the rocket an initial acceleration of $9 . {8 ms}^{- 2}$ ?

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A 4000 kg rocket is fired. If the exhaust speed is 500 ms–1 , how much gas must be ejected per second to supply the thrust needed, (a) to overcome the weight of the rocket, (b) to give the rocket an initial acceleration of 9.8 ms–2 ?

Remember concepts with our Masterclasses.

Ready to Test Your Skills?

free study material

A 4000 kg rocket is fired. If the exhaust speed is $500 {ms}^{- 1}$ , how much gas must be ejected per second to supply the thrust needed,
(a) to overcome the weight of the rocket,

(b) to give the rocket an initial acceleration of $9 . {8 ms}^{- 2}$ ?