Schrodinger's Wave Equation

By the way Who loves Schrodinger's wave Eqn here. I have a question, please help to solve. It certainly goes at most times above my head!

Q1: Show that the angular wave number k for a non relativistic free particle of mass m can be written as

k = \frac{2\pi \sqrt{2mK}}{h}

Where K is the Kinetic Energy of the Particle.

P.S. h = h 'cross' or \frac{h}{4\pi}