How Do You Calculate Spring Constant and Mass for Oscillations?

[dynamity]

Homework Statement

A 200 g mass elongates a spring 3 cm from its equilibrium position. Find the spring constant (k) of the spring in N/m.

An unknown mass is attached to the same spring and set in motion. If the period of oscillation is 3 seconds, find the value of the unknown mass in kg.

Homework Equations

k=mg/x
T=2pi(sqrt)(m/k)

The Attempt at a Solution

I think I've determined part A to be 65.4 N/m. I did this by converting cm->m and g->kg. Then I filled it into the equation...

k=.2(9.81)/.03 = 65.4 N/m

Then I plug it into the other equation for part two of the question

3=2pi(sqrt)m/65.4
3/2pi (changed to .477 for ease)=sqrt(m/65.4)
.477^2=(m/65.4)
.22797=m/65.4
.22797(65.4)=m
m=14.91 kg

Mostly what I'm asking for here is a confirmation on my work and if the m at the end of my second equation comes directly in kg or if it needs to be converted first.

 

[rl.bhat]

Hi dynamity, welcome to PF.
Your answer is correct. Final answer is in kg. No need to convert to any thing.