We have been given a set of questions to do. Most of these I have managed fairly easily but there are some which I am really stuck on and am getting quite annoyed with now as I have been working at them for ages! Help on any of these would be really appreciated:(adsbygoogle = window.adsbygoogle || []).push({});

The Saturn V rocket which launched the Apollo space missions had the following specifications:

mass at lift-off = 3.0 x 10^6 kg

velocity of exhaust gases = 1.0 x 10^4 m/s

initial rate of fuel consumption at lift-off = 3.0 x 10^3 kg/s

1.(a) Calculate:

(i) the force (thrust) produced at lift-off

(ii) the resultant force acting on the rocket at lift-off

2.(a) An empty railway truck of mass 10000kg is travelling horizontally at a speed of 0.5m/s. (had to calculated the momentum and kinetic energy - not sure if this will help with the bit im stuck with!)

Sand falls vertically into the truck at a constant rate of 40kg/s. Calculate the additional horizonal force which must be applied to the truck if it is to maintain a steady speed of 0.5m/s.

Thanks for anyones help - I can usually manage these kind of questions but I'm really stuck for some reason!!

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# Homework Help: Some mechanics questions

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