A horizontal force of 87.7 N is applied to a 28.5 kg crate on a rough, level surface. If the crate accelerates at 1.13 m/s2, what is the magnitude of the force of kinetic friction (in N) acting on the crate

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?