# Compound/Physical Pendulum

1. Mar 10, 2008

### Pete2008

Find the acceleration due to gravity using a compound/phyiscal pendulum. Using the formula: T=2pie*sqrt(I/mgh)

I understand how to find all the variables but to find g, i must plot a graph of T against something (Thats where i need help) and use the gradient of the line to calculate g.

so.

1.What do i plot against T
2.How would i calculate g from the gradient of the line

Thanks.

2. Mar 10, 2008

### Hootenanny

Staff Emeritus
Hi Pete and welcome to PF,

Firstly, what is the general equation of a straight line?

3. Mar 11, 2008

### Pete2008

Hi,

The equation of a staright line is y=mx+c, and i guess that T would be the y axis/ the y part of the equation. Would the x axis of the graph be I, because thats the variable I am changing by moving the mass along the rod?

Once I know the x and y part of the equation would it just be a case of rearanging the origional formula into y=mx+c?

Thanks

Last edited: Mar 11, 2008
4. Mar 11, 2008

### Hootenanny

Staff Emeritus
Absolutely spot on

5. Mar 11, 2008

### Pete2008

Thanks alot

6. Mar 11, 2008

### Hootenanny

Staff Emeritus
No problem, I didn't do anything...:uhh: