1. A car moves 20 m/s east for 5 sec, 10m/s north for 10 sec and then 30m/s west for 5 sec. Calculate a) displacement b) average velocity
2. A cyclist ride his half journey at 10 m/s and the rest at 8 m/s. calculate his average speed.

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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?