3. A penny is dropped from the top of the Eiffel Tower. After falling uninterrupted for 2s, the penny is a distance D from where it was dropped.
Assuming a constant gravitational acceleration, how far below the top of the Eiffel Tower is the penny
after falling for a total of 4s?

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?