Question

Suppose you are on an airplane moving at high speed. If you flip a coin straight up it will land in your lap rather than a great distance behind you. Explain why this is true and include any laws that help prove your point.

Answer 1

It will land in your lap because there's different frames of motion relative to yourself. For example, if you're running at a speed of 6 mph, it doesn't mean you'll run as fast as the Earth spins. Also, since you're on the interior of the plane, any kind of wind or weather on the outside will not affect the coin. A law to back up this claim is Einsteins Special Law of Relativity.

Answer 2

You don't need relativity to explain this. Only good old Newtonian mechanics. You are moving horizontally at high speed. You're holding the coin in your hand so the coin is also moving horizontally at high speed. If you toss it up temporarily it continues moving horizontally just like your lap.