OK thanks. It doesn't seem like enough but I'll look deeper into the Oberth Effect, and do some maths, and hopefully it'll make sebse (before, I worked out the mass of fuel, but just assumed the rocket's mass was constant).
Well, I thought I understood it until you said that. How can the fuel consumption relate to momentum, when there is a finite amount of energy stored in the fuel? Seeing as the problem I had in the first place was with a body NOT connected to the ground, the rocket model is more accurate. So as I...
I see what you mean. Thank you for being so patient, I finally understand what is wrong. I'll do some maths with the rockets and exhaust etc. but I'm sure you'll be right in the end. Thanks.
The force on the output would decrease by half. The wheels will not have as much torque. Is that what you're looking for? But this just shows that if the input rpm is cut in half, half as much fuel is being used, and therefore the fuel used is still proportional to the force. I'm sorry I don't...
But surely the same amount of fuel is going into the engine per stroke of the piston - the volume of it doesn't change, and the explosive force it provides must be the same for every stroke? So if it is a 1 litre engine, surely the amount of gas burnt per minute is always 1 litre * the RPM. How...
Thanks for pointing out the Oberth Effect - I'd never heard of it and didn't consider that the fuel itself has kinetic energy. At some point I'll do some Maths and see if it satisfies the problem. I apologise for mentioning efficiency - I didn't mean it in the traditional sense, I just meant...
Yes, and it makes the problem even worse. With the first case, say for each of the accelerations 10 kg of fuel is expelled at 1 m/s for 10 seconds. The KE if the fuel is 80 J, so the total KE of the rocket and fuel is 130 J. After the second acceleration, the total KE is much more - 1180 J. If...
I do understand how these are defined, but that is what has caused the problem. I don't see how there can be a massive increase in energy for something moving in orbit (for instance), compared to something that is stationary. The KE increase would be thousands if times greater, even though the...
OK, thanks for replying.
If it takes more power, how does the engine 'know' how fast it is going in order to be less efficient? If you were to just leave it running at the same power, assuming no external resistance, the force produced would gradually decrease as the body accelerates. I don't...
I am not aware of a named force that will rotate an axis that is rotating itself, but there is a force that resists this - it is actually quite hard to change the position of a rotating axis, due to gyroscopic precession en.wikipedia.org/wiki/Precession. This could also be regarded as a pseudo...
I apologise for what is probably merely stupidity on my part, but has been vexing me for rather a while, and no one I ask can provide any insight.
A body undergoes two accelerations. The first is from 0 to 10 m/s, the second from 10 to 20 m/s. For simplicity's sake I will say F= 1N, a= 1 m/s2...