Consider a particle of mass m moving in a one-dimensional box under the potential $\mathrm{V}=0$ for $0 \leq \mathrm{x} \leq \mathrm{a}$ and $\mathrm{V}=\infty$ outside the box. When the particle is in its lowest energy state the average momentum (< $\mathrm{p}_{\mathrm{x}}>$ of the particle is