How Efficient Are Human Leg Muscles?

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Homework Help Overview

The discussion revolves around the efficiency of human leg muscles, specifically focusing on calculations related to output energy and input energy, including the role of heat in these calculations.

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  • Mixed

Approaches and Questions Raised

  • Participants are discussing the calculations for output energy and questioning the correctness of their results. There is also a query regarding the expected temperature change in the muscles.

Discussion Status

Some participants have provided insights into the relationship between work and heat in the context of energy efficiency. However, there appears to be confusion regarding the information provided about heat generation, with multiple interpretations being explored.

Contextual Notes

There is a noted lack of clarity regarding the information about heat generation, which is essential for calculating input energy. Participants are referencing specific values and assumptions from the problem statement.

coconut62
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Please refer to the image attached.

For Q5, I did it like this:

Output energy = (50kg x 10 x 0.35metre) x 30times x 4minutes

And divide the answer by 120kJ.

The percentage I got is 17.5 Joules but the answer is 15J.

Did I do anything wrong?

For Q6, the temperature should fall, correct?

Thanks in advance.
 

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The muscles did work and produced heat. So the input energy is work+heat. The efficiency is output energy divided by input energy.

ehild
 
But there are no informations about heat.
 
coconut62 said:
But there are no informations about heat.

Read the problem text: "The muscles generate 120 kJ heat".

ehild
 

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