Q1. A 500 g rubber ball is dropped from a height of 10 m and undergoes a completely elastic collision with the earth.
a) What is the earth's velocity after the collision?
Suppose the earth was at rest just before the collision.
b) How many years would it take earth to move 1.0 mm at this speed?
Q2. Eight identical, non-interacting particles are placed in a cubical box of sides L = 0.2 nm.
Find the lowest energy of the system (in electron volts) and list the quantum numbers of all occupied states if (a) particles are electrons and (b) particles have the same mass as the electron but do not obey the exclusion principle.