2. Find the period of motion for a 200 gram mass vibrating on a spring having a spring constant of 4.0 n/m?

3. When a mass of 35.0 grams is attached to a certain spring, it makes 20 complete vibrations in 4.80 seconds. What is the spring constant for this spring?

equations: SHM: T=2pi sqr(m/k)

1. i have no idea...really

2. t=2pi sqr(200g/4 n/m) = 44.4288

3. k=4pi^2m/t^2

k=4pi^2(35g)/(4.1s)^2 [t=4.1s]

k=82.19 N/M

I dont understand the spring constant equation.

Please help?