Why is a jet’s performance measured with linear force but an engine’s performance is measured in power?
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Because the point of a jet is to go really fast and you do that with linear force.
The point of an engine is to have a bunch of power to do something. Maybe that something is to go really fast in a straight line, maybe it’s not. Maybe the engine produces power to do something else.
Jets and rockets are momentum engines. Your car engine provides energy
Thrust from a jet engine really comes from the change in momentum of the air that runs through it. A turbo fan takes a huge amount of air through the fan and accelerates it just a tiny bit to generate a large impulse (change in momentum) that’s not really connected to the energy put in from the fuel. If you can get more air and accelerate it less then you get the same thrust with less energy. How fast the plane accelerates is based on the thrust/impulse
Your car engine is extracting energy from the expanding gas and then passing the energy down to the wheels. It only deals in energy not momentum and energy over time is power
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