given a strong chain and a convenient tree, could you pull your car out of a ditch in the following way? fasten the chain to the car and to the tree. pull with a force f at the center of the chain as shown in the figure. from mechanics, we have f = 2t sin, or t = f/(2 sin θ), where t is the tension in the chain, that is, the force exerted on the car tree car 20 ft

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?