1. The problem statement, all variables and given/known data A hanging spring stretches by 30.0 cm when an object of mass 500 g is hung on it at rest. We define its position as x = 0. The object is pulled down an additional 16.5 cm and released from rest to oscillate without friction. What is its position x at a moment 84.4 s later? 2. Relevant equations Fs = -kx Fs = mg x(t) = Acos(ωt + ∅) w = (k/m)1/2 w2 = k/m T = 2∏/w E = (1/2)kA2 E = (1/2)mv2 + (1/2)kx2 v = =- [ (k/m)(A2 - x2) ]1/2 3. The attempt at a solution m = 0.5 kg All I can do right off the bat is solve for k Fs = (9.8 m/s2)(0.5kg) = 4.9N 4.9N = -kx 4.9N = (-k)(-0.3m) k = 16.33 N/m Now solve for ω ? w = [ (16.33 N/m) / 0.5 kg ]1/2 ω = 5.7 s-1 Not sure where to go from here regarding energy and I'm afraid that if I plug in to x(t) = Acos(ωt + ∅) it would be wrong?