Ex. problem. A plane is flying 140m above the surface. A parachutist drops out of the plane and lands 60m from where he jumped out. What is the plane's velocity? I used the Pythagorean theorem to find the displacement of the parachutist, i.e. the hypotenuse. I then multiplied the parachutist's displacement by two times the acceleration of gravity. The product would be some velocity squared. I don't know if this is the correct velocity, so I'm wondering how to find that.