1. a 1 kg hockey puck is moving at 10 m/s across the ice. at the other end of the ice rink, its speed is measured at 9.2 m/s. if the puck traveled 60
m, how much friction force acted on the puck? (assume the friction force was constant the whole time).

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?