Two balls, each with a mass of 0.876 kg, exert a gravitational force of 8.57 x 10-11 N
on each other.
How far apart are the balls? The value
of the universal gravitational constant is
6.673 x 10-11 Nm²/kg?.
Answer in units of m.

An electron is trapped at a defect in a crystal. the defect may be modeled as a one-dimensional, rigid-walled box of width 1.00 nm. (a) sketch the wavefunctions and probability densities for the n 1 and n 2 states. (b) for the n 1 state, nd the probability of nding the electron between x1 0.15 nm and x2 0.35 nm, where x 0 is the left side of the box. (c) repeat (b) for the n 2 state. (d) calculate the energies in electron volts of the n 1 and n 2 states