A long platform is holding your physics teacher in the air above some hungry alligators. Your physics teacher has a mass of 75 kg and is located 2 m from one end. The 10.0 m platform has a mass of 10.0 kg, and its center of gravity is located 4.0 m from the same end. The platform is being held up by two students, one at either end. a. What force is required by each student to hold the platform up?

The nuclear potential that binds protons and neutrons in the nucleus of an atom is often approximated by a square well. imagine a proton conned in an innite square well of length 105 nm, a typical nuclear diameter. calculate the wavelength and energy associated with the photon that is emitted when the proton undergoes a transition from the rst excited state (n 2) to the ground state (n 1). in what region of the electromagnetic spectrum does this wavelength belong?