Question about elastic energy

  • #1
Clara Chung
304
14

Homework Statement


56.png


Homework Equations




The Attempt at a Solution


I tried to use the equation introduced in the class, E=σε/2
ε=αΔT =2*10-5*200 = 4*10-3
and by σ=Yε, I get σ=110*109*4*10-3 = 4.4*109
so E=(4*10-3) * (4.4*109 ) /2 = 880000J
Why am I wrong?
The correct answer is 35.2 J
 

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Answers and Replies

  • #2
22,231
5,133
Better check your units. Also, you determined the stored energy per unit volume.
 
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  • #3
Clara Chung
304
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Better check your units. Also, you determined the stored energy per unit volume.
Thanks!
 

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