Answer:
1) F = - K X where F is the restoring force and K the spring constant
F = 31.2 N/m * (.873 - .558) m = 9.83 N
a = F / m = 9.83 / 1.70 = 5.78 m/s^2
2) ω = (K / m)^1/2 = (31.2 / 1.70)^1/2 = 4.28 / s
Vmax = ω A = 4.28 / s * (.873 - .558) m = 1.35 m/s
(note also a = ω^2 A = 4.28^2 * (.873 - .558) = 5.77 the result of (1))
(3) f = ω / (2 * π) = 4.28 / (2 * 3.14) = .681 / s frequency of vibration
P = 1 / f = 1 / .681 = 1.47 s period of oscillation
P / 4 = .367 s time for 1/4 oscillation
(4) Since ω is constant for the conditions given the time to return to the origin does not depend on the amplitude of oscillation