Apurple beam is hinged to a wall to hold up a blue sign. the beam has a mass of mb = 6.2 kg and the sign has a mass of ms = 17 kg. the length of the beam is l = 2.48 m. the sign is attached at the very end of the beam, but the horizontal wire holding up the beam is attached 2/3 of the way to the end of the beam. the angle the wire makes with the beam is θ = 33.2°.

Materials will have different energies associated with the electrons inside them. this is related to how strongly bound they are by their work function. if we sandwich a material with a very low energy between two materials with a high energy, we create a trap for an electron. if this trap is very narrow in one direction in comparison to the others, this is approximately a 1-dimensional box that confines the electron. what is the lowest energy of an electron in the box if the thinnest direction across the materials is 4.81 nm?