But on a whole other level, it's completely not obvious, especially this moving uniformly straightforward. So this right here, this would be a balanced force. And, indeed, one of these gentlemen is Sir Isaac Newton. There's really no way for me to tell whether that airplane is moving without looking out the window. Or if I throw a tennis ball. And the reason why Galileo, frankly, was probably good at thinking about that is that he studied the orbits of planets.
So if I'm sitting in the airplane right over here.
More on Newton's first law of motion
Your car won't go forever, unless you keep, unless the engine keeps burning fuel to drive and consuming energy. There's no way for me to sense that the plane is moving. Let's say that I have a rock. This, you know, something that's at rest will stay at rest, unless it's being acted on by an unbalanced force. Newton's third law of motion. Everything in human intuition says if you want something to keep going in motion, you have to keep putting more force, keep putting more energy into it for it to keep going.