At what point on the track does a roller coaster have the greates kinetic energy?

Why does the input force have to be greater than the force needed to lift the bale?

Aphoton is absorbed by an electron that is in the n = 3 state of a hydrogen atom, causing the hydrogen atom to become ionized. very far away from the nucleus, the released electron has a velocity of 750,000 m/s. what was the wavelength of the absorbed photon?

What is the single most important equation in all of physics?