physics
posted by Elisa on .
Determine the elongation of the rod in if it is under a tension of 5.7E10^3 N.
The rod is made of aluminum and copper. From the aluminum to the copper section it measures 1.3m and from the copper section to the end it measures 2.6m with a radius of 0.2cm.
Can someone please help, I honestly don't know where to begin.

Add the elongations of the aluminum and copper sections. The elongation of each is
delta L = L * T/(AY)
Where L is the length of that material, A is the cross sectional area and Y is Young's modulus, which you will have to look up.
For copper:
L = 2.6 m
A = (pi)*(2*10^3 m)^2
Your text should have Young's modulus values for aluminum and copper; otherwise try googling it. 
You can find Young's modulus values for many materials, including copper and aluminum, at
http://en.wikipedia.org/wiki/Young's_modulus
It is represented by the symbol E there, not Y.
For copper is it about 120* 10^9 N/m^2 .
They use the units of GigaPascals (GPa), which is 10^9 N/m^2. 
Thank you very much!