A mass of .4 kg, hanging from a spring with a constant of 80 N/m, is set into an up-and-down simple harmonic motion. What is the speed of the mass when moving through a point at .05 m displacement? The starting displacement of the mass is .10 m from its equilibrium position. * zero * 1.4 m/s * 1.7 m/s * 1.2 m/s I am confused with this one. I don't know where to begin. Any help would be appreciated. I need to have this done by Monday. Thanks.