9. A 1.0 kg block oscillates on a spring with the spring constant 20 N/m. Right is the positive direction. At t : Us the block is 20 cm to the right of the equilibrium position and moving to the left at a speed of lOOcm/s. Determine the phase constant of the oscillation. (a) 2.056 rad (b) 0.841rad (c) 0.020 rad (d) 0.999 rad (e) 0.437 rad