A mass weighing 4lb stretches a spring 8 in. If the mass is pushed upward, contracting the spring a distance of 8 in and then set in motion with a downward velocity of 2 ft/s, and if there is no damping and no other external force on the system, find the position u of the mass at any time t. Determine the frequency (wo), period (T), amplitude (R), and phase (8) of the motion. NOTE: Enter exact answers. Use t as the independent variable. u(t) -

A mass weighing 4lb stretches a spring 8 in. If the mass is pushed upward, contracting the spring a distance of 8 in and then set in motion with a downward velocity of 2 ft/s, and if there is no damping and no other external force on the system, find the position u of the mass at any time t. Determine the frequency (wo), period (T), amplitude (R), and phase (8) of the motion. NOTE: Enter exact answers. Use t as the independent variable. u(t) -