Find the spring constant by timing simple harmonic motion. I have done a Hooke's law experiment already and found out about initial tension. What I learned was: force ≠ spring constant x displacement force = initial tension + (spring constant x displacement) So using F=kx would not give an accurate value for k, it would over-estimate it by including initial tension. My question is would the equation T=2π√(m/k) give the 'true' value of k or would it give the over-estimated value? The two are so close I can't tell which my results are showing.