system
Given the following post, respond as if you're commenting on Reddit:
human
Why does an alternator turn slower, or resist turning more when under load?

I noticed this in my car when I would activate something that draws electricity like window motors, the engine RPMs would drop slightly until I let off the window motor button. Is this a stupid question and I'm totally wrong about what's actually happening to cause the engine RPMs to dip while there's an electrical load? Thank you for any useful input!!
gpt
There's different levels you can look at it from. The simplest is conservation of energy. If it didn't turn slower under load, you'd have more energy when you give it a load than when you don't. It could be creating energy, or it could be destroying it when you don't use a load, but either way that's not conserving energy.

But looking at the underlying physics itself, it's because when it's under load, you have a magnet moving through coils to generate electricity, and the electricity moving through those coils generates a magnetic field in the opposite direction.