Suppose that the speed of an electron traveling 2000 m/s is known to an accuracy of 1 part in (i.e., within 0.001%). What is the greatest possible accuracy within which we can determine the position of this electron?

Heisenberg's Uncertainty Principle: The position and momentum of a particle cannot both be measured precisely at the same time.

The Pauli exclusion principle: No two electrons in an atom can occupy the same quantum state.