Calculating Force Using Young's Modulus

[MissAlex]

1. How to calculate cross sectional area and force for Young's Modulus? My main issue is that I don't know my F or my A_o. Help?
e=Constant 2.10⁶
DeltaL=10mm
L_o (original length of elastic)= 200mm
f=?
A_o=?

2. E= FL_o
A_o(Delta)L
F= EA_oDeltaLength[U/]
L_o
F= (2.10⁶)(10mm)(A_o)
200mm

3. There are two unknown variables! How can I do this?

 

[radou]

Interesting. From the given change in length and original length, you can calculate the strain. Then you can multiply with E to obtain the stress. But you can't calculate the area if the force is unknown, and vice versa.

 

[MissAlex]

Right.
What is the force though? How can force be calculated?
How is cross-sectional area calculated?