# Strain and force

1. Oct 2, 2009

### Ry122

If I know only the length of the beam, the young's modulus, and the cross sectional area, is there an equation that I can use to determine what amount of force would be required to lengthen a beam by a specified amount? The force is being applied to the beam axially.

2. Oct 2, 2009

### FredGarvin

$$\delta = \frac{PL}{AE}$$

3. Oct 3, 2009

### Ry122

$$\P = \frac{deltaAE}{L}$$

Using this with
delta=.4421207mm
E=200,000MPA
A=5776mm
L=701mm
The force is 728584640N
Doesn't this seem like too much?

4. Oct 3, 2009

### FredGarvin

Check your units. Convert all of the mm to m.

5. Oct 3, 2009

### Ry122

That's what I did. mm have prefix 10^-3
and Mega pascals has 10^6