Heat Engine Carnot Efficiency question

AI Thread Summary
A heat engine with a Carnot efficiency of 0.11 is tasked with performing 5.1 x 10^4 joules of work. The relationship between work (W), heat (Q), and internal energy (U) is crucial for solving the problem, as expressed in the equation ΔU = Q - W. The user initially struggles to understand how to calculate the internal energy and exhaust heat but later estimates internal energy at 412,636 joules, suggesting that exhaust heat is equivalent. Understanding thermal efficiency is key to relating Q and W to the engine's efficiency.
DrDonaldDuck
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Homework Statement


A heat engine has a carnot efficiency of 0.11. How much internal energy does this engine use in order to do 5.1 x 10^4 joules of work? How much heat does this engine give off/exhaust?

Homework Equations


(change in)U=Q-W
W=(change in)E
 
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You need to post your attempt.

How does W and Q relate to the efficiency?
 
rock.freak667 said:
You need to post your attempt.

How does W and Q relate to the efficiency?

W is the work done and Q is the heat generated. U is the total internal energy. No idea how to do this, hence my non-existent attempt.
 
Still stumped and don't know how to attack problem!
 
Someone PLEASE help?!? Growing very desperate here.
EDIT:
I think I got it.
Internal energy=412636J, exhaust heat is the same. So sleepy, please confirm.
 
Last edited:
Look up 'thermal efficiency', that will tell you how Q and W are related to the efficiency n.

When you know that you can get the value of Q and subsquently U.
 

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