EXAMPLE 2.1 The screw eye in Fig. 211a is subjected to two forces. E, and Fz
Determine the magnitude and direction of the resultant foree.
15°
F = 150N
F, = 100 N

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?