- #1
Stewart Snider
Consider a rocket engine held stationary that produces 1000 kg of thrust.
Now, allow that engine to move on a track at, say, 100m/s, controlling its velocity with a brake, keeping the fuel burn rate the same. The brake will get hot.
But since the fuel burn rate remains the same, the rocket's heat output remains the same as well, right? All we've done is allowed the thing to move. But with movement, we're generating heat in the brake in addition to the rocket exhaust. It would seem we're getting the heat from the brake for free. This violates the law of conservation of energy, so I know there must be a flaw here.
Can anyone tell me what I'm missing?
Now, allow that engine to move on a track at, say, 100m/s, controlling its velocity with a brake, keeping the fuel burn rate the same. The brake will get hot.
But since the fuel burn rate remains the same, the rocket's heat output remains the same as well, right? All we've done is allowed the thing to move. But with movement, we're generating heat in the brake in addition to the rocket exhaust. It would seem we're getting the heat from the brake for free. This violates the law of conservation of energy, so I know there must be a flaw here.
Can anyone tell me what I'm missing?