# SHM Help

1. Oct 10, 2013

### southport

SHM Help!!!!

Using a program called tracker we have got data from a spring holding a 0.5 kg weight. We have the displacement in the x direction (positive x direction being down) and time. The task is to somehow find the spring constant (k) but I cannot for the love of me figure it out. Any help is greatly appreciated and this is urgent!!!!

2. Oct 10, 2013

### Mentz114

Set the spring in a spring balance configuration and measure its extension for different weights. The slope of the distance vs weight graph is the spring constant. Units are force/distance.

See here http://en.wikipedia.org/wiki/Simple_harmonic_motion

3. Oct 10, 2013

### southport

Mentz114, this is a homework question and we don't have access to anymore testing, according to my teacher this is enough information.

4. Oct 10, 2013

### Mentz114

What data do you have ? You need to know the frequency then you can use the formula $f=(1/2\pi)\sqrt{k/M}$.

5. Oct 10, 2013

### southport

The only data we have is displacement as a function of time!

6. Oct 10, 2013

### nasu

Does you displacement look periodic? Find the period.

7. Oct 10, 2013

### Staff: Mentor

Plot a graph of the data, with time as the abscissa and displacement as the ordinate. From this graph, you should be able to visually tell what the period of the oscillation is. Assuming you know the relationship between the period and the frequency, you can then use Mentz114's formula to calculate the spring constant.

8. Oct 10, 2013

### Mentz114

Do a Fourier analysis of the data !