Chemical energy in the runner's body

AI Thread Summary
In the discussion about chemical energy transformation in a runner's body, participants debated the correct answer to a test question regarding energy conversion during running. While one participant initially chose kinetic energy, the consensus emerged that most chemical energy is transformed into thermal energy due to heat loss during muscular activity. The conversation highlighted that running on level ground does not involve potential energy, and there is no change in kinetic energy since speed remains constant. Additionally, it was noted that muscular movement involves a combination of electrical signals and chemical processes. Ultimately, the transformation of energy during running primarily results in thermal energy, reflecting the inefficiencies in human energy use.
courtneylane8
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So I got back a test and one of the questions was the following: A person is running at a constant speed on level ground. Chemical energy in the runner's body is being transformed to other forms of energy: most of the chemical energy is transformed to?
a. thermal energy
b. potential energy
c. kinetic energy

I chose kinetic energy but the correct answer is thermal. Do anyone know how to explain why?
 
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I probably would have chosen kinetic as well, but thermal makes sense, because a lot of human's energy is wasted by becoming heat rather than kinetic.
 


courtneylane8 said:
So I got back a test and one of the questions was the following: A person is running at a constant speed on level ground. Chemical energy in the runner's body is being transformed to other forms of energy: most of the chemical energy is transformed to?
a. thermal energy
b. potential energy
c. kinetic energy

I chose kinetic energy but the correct answer is thermal. Do anyone know how to explain why?

Well ... it's not up hill ... there goes potential energy as a possibility.
There is no change in velocity ... so there goes any change in kinetic energy.
 


That is a bad question. There are various forms of energy in that given situation. Both A and C are correct.

There's heat transfer going on between the body and the ambient environment. However, there's electrical energy, kinetic energy, and chemical energy involved, as well.

Muscular movement is a combination of electrical signals and chemical motion (Through Fickian diffusion and biological motors).

Muscular movement results in kinetic energy.


EDIT: But Lowly, it doesn't say if there's change in KE. It just says what is the energy being transformed to. The change in KE could be 0, but there's KE.
 


Thank you all!
 


womfalcs3 said:
EDIT: But Lowly, it doesn't say if there's change in KE. It just says what is the energy being transformed to. The change in KE could be 0, but there's KE.

For this kind of question I don't think it matters. Whatever the internal energies of the system, the pumping of the arms and pounding of the legs, the impact of the shoes, muscles pulling tendons and bones about, the kinetic energy converts to thermal energy readily enough. For the kind of introductory question it is, I'm sure there is no intent to get esoteric about chemical/biological processes.

Besides, I suspect when viewed over a complete stride it is mostly thermal after accounting for the energy state changes.
 
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