you--woop. okay? and you feel that lurch. you can feel the effect of acceleration. is there any other controls on the car that will make it change how it's moving? beginning with a b, end with rake. try it. brake. your brake. and when you slam on the brake, what happens? poom. everyone pitches forward. you can feel it. because there's a change. you can feel that change. is there another control in your car that will make it accelerate? the steering wheel. steering wheel. that's right. you're driving on the road and you take that steering wheel, you go like this. woop. everyone on the car lurches to the side. you can feel the effect of acceleration. interestingly enough, if you're moving at steady speed with no acceleration, not only can you not feel that you're moving, you really have no proof that you're moving at all. let's suppose you're in an airplane, the pilot's at 600 miles an hour, but you look out and everything seems to be at rest. you take a coin, you flip it. it behaves just the same way as if you're at rest. all the little devices you can put on board,