A baseball player (mass = 75 kg) is running north towards a base. In order to avoid being tagged by the ball, the baseball player slides into the base. If his acceleration
in the slide is 5.0 m/s2 south, what is the kinetic frictional force between the
baseball player and the ground?

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?