- #1

MattGeo

- 26

- 3

I know that one could say that according to the observer on the ground that the car provides a force over a longer distance and hence more work must have been done in that reference frame to accelerate, and hence, more energy. But if you're in 1 of the cars watching the other car accelerate from 0 to 10 m/s according to you, wouldn't that be the same if the stationary observer had watched the same car accelerate from 0 to 10 m/s? the change in energy would be the same, but the fuel consumed can't be the same for each of those cases for the stationary observer. He'd see less fuel consumed from in the 0 to 10 m/s interval than in the 10 to 20 m/s interval.

If I am in the car moving at 10 m/s next to the other car doing the same, and I watch him accelerate "from rest" to 10 m/s, wouldn't that be more fuel used than if the stationary observer had watched the car accelerate from rest to 10 m/s? I can't really make sense of where I am going wrong and keep confusing myself.