Consider a free particle of mass m. Show that the position and momentum operators in the Heisenberg picture are given by
x^H(t)=x^H(0)+m1p^H(0)tp^H(t)=p^H(0).
Comment on the relationship between these equations and the classical equations of motion. *Hint*: you will first need to evaluate the commutator [x^,H^n]; this will allow you to evaluate the commutator [x^,U^].