8.
objects tend to "keep on doing what they're doing" (unless acted upon by an unbalanced force). when your car abruptly stops, the seat belt provides the that brings you from a state of motion to a state of rest.

a. spring force
b. unbalanced force
c. friction force
d. gravity force

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?