Describe a car's velocity as it goes around a track at a constant speed

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

This is the number of complete movements of a wave per second.

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?