Aweightlifter’s barbell consists of two 25-kg masses on the ends of a 15-kg rod 1.6 m long. the weightlifter holds the rod at its center and spins it at 10 rpm about an axis perpendicular to the rod. what’s the magnitude of the barbell’s angular momentum?

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?