This is about Elastic Springs.. so far I've answered every question. This is the only one I don't get. It's so confusing for me..

In the laboratory, you attach 300 g mass to a spring of negligible mass and start oscillating it. The elapsed time from when the mass first moves through the equilibrium position to the second time it moves through that position is 2 s. Find the force constant of the spring

1 answer

The oscillation period is P = 2.0 s.

Use the formula

P = 2*pi*sqrt(M/k)

with M = 0.300 kg

Solve for k in Newtons per meter

k = 4*pi^2*M/P^2