I am so sorry that I have disturbed you
I did not read all the thread, that is why I said it was too much homework. And I missed the "if it was a car"
I'm sorry for having bothered you. -1 for me.
I just think it is fun thinking about these matters. I like it. I used to do it a lot, with paper, pen and a calculator. Sometimes with a friend, writing in the back of a newspaper. I was not trying to teach you anything new, only to share the fun with you, because I like it too.
As for the -2... Why -2?
I still remain convinced that piston engines are power producing machines. Yes, we have to take into account a lot of losses, thermal efficiency, etc... But they deliver power per each pound per hour. That's a fact. After that you can do whatever you want with that power. Like producing pounds of thrust and speed, for instance.
In stead of remarking my own humble "I am no physics teacher" you should study take off physics a little bit more, in the first place, if you are so interested in the subject. You would learn, for instance, that you need integrals to compute thrust, acceleration, distance and Lift as they change all throughout the take of roll (Why did you think there is no lift until VR?).
But you want to know how much power would a 747 engine require to take off if it was a big car engine coupled to the wheels, right?
I suggest you to find the take off roll distance and the average thrust during the take off roll for a typical 747. Multiply them (energy delivered to the 747) and divide the result by the time required. That is the power used (rate at which
Work is applied).
