Kai was 200 meters north of the library when he remembered he had to return some books to the library. it took him 200 seconds to do the round trip. which best describes kai's roundtrip? his speed was 1 m/s, and his velocity was 0. his speed was 2 m/s, and his velocity was 0. his speed was 1 m/s, and his velocity was 1 m/s north. his speed was 2 m/s, and his velocity was 2 m/s south.

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?