What is the change in length of an aluminum rod after adding 12500 J of energy?

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SUMMARY

The discussion focuses on calculating the change in length of an aluminum rod after adding 12,500 J of energy. The rod, initially 23.0 cm long at 20°C with a mass of 350 g, undergoes a temperature change calculated using the equation Q = m * c * delta T. The final temperature is determined to be 59.68°C, leading to a change in length calculated with deltaL = alpha * L0 * deltaT, where alpha is 24 x 10^-6 and c is 900 J/kg. The correct change in length is 0.219 mm, highlighting the importance of proper unit conversion in calculations.

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Homework Statement


An aluminum rod is 23.0 cm long at 20°C and has a mass of 350 g. If 12500 J of energy is added to the rod by heat, what is the change in length of the rod?

Answer is in mm

Homework Equations


Q=m*c*delta T
deltaL=alpha*L0*deltaT
alpha=24x10^-6
c=900j/kg


The Attempt at a Solution


12500=.35kg*900(Tf-20C)
Tf=59.68

deltaL=24x10^-6*.23m*39.68
The answer I get is 2.19*10-4m which is wrong
That /1000 to get mm is 2.19*10-7 which is wrong

I don't understand what I did wrong...
 
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Isn't 2.19*10-4m = .219 mm?
 
Whoops...divided instead of multiplied. Thanks.
 

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