In a loading a lorry a man lifts boxes each weight 200N through a height of 3.5m. a). How much work does he do in lifting one box?
b). How much energy is transferred when one box is lifted?
c). If he lifts four boxes per minute at what power is he working?

Aparticle of mass m is placed in a one-dimensional box of length l. the box is so small that the particle’s motion is relativistic, so that e p2/2m is not valid. (a) derive an expression for the energy levels of the particle using the relativistic energy–momentum relation and the quantization of momentum that derives from connement. (b) if the particle is an electron in a box of length l 1.00 1012 m, nd its lowest possible kinetic energy. by what percent is the nonrelativistic formula for the energy in error?