A boy exerts a horizontal force of 119 N on a crate with a mass of 33.2 kg. If the crate doesn't move, what's the magnitude of the static friction force (in N)?
What is the minimum possible value of the coefficient of static friction between the crate and the floor? (Assume the crate remains stationary.)

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?