Amass m = 1.3 kg hangs at the end of a vertical spring whose top end is fixed to the ceiling. the spring has spring constant k = 85 n/m and negligible mass. the mass undergoes simple harmonic motion when placed in vertical motion, with its position given as a function of time by y(t) = a cos(ωt – φ), with the positive y-axis pointing upward. at time t = 0 the mass is observed to be at a distance d = 0.45 m below its equilibrium height with an upward speed of v0 = 5 m/s. a. find the angular frequency of the oscillation in radians per second. b. find the smallest positive value of ϕ in radians. c. calculate the value of a in meters. d. what is the mass's velocity along the y-axis in meters per second at time t1 = 0.15 s? e. what is the magnitude of the mass's maximum acceleration in meters per second squared?