How Much Elastic Energy Is Stored in the Achilles Tendon?

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The discussion centers on calculating the elastic energy stored in the Achilles tendon using the maximum tension of 4.5 kN and a spring constant of 360 kN/m. The correct formula derived from Hooke's Law is Energy = 1/2 * k * x squared, where x is determined to be 0.0125 m. Initial calculations yielded an incorrect energy value of -0.0281 kJ, prompting questions about unit conversions. It was clarified that the spring constant should be converted to N/m, and the final energy value should be positive, indicating the correct approach to the problem.
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Homework Statement


If the maximum tension in the Achilles tendon when the foot is sent down is 4.5 kN and the tendon's spring constant is 360 kN/M, calculate how much elastic energy is stored in it.

Homework Equations


F = kx
Hookes Law: Energy = 1/2*k*x squared

The Attempt at a Solution


Got x from F = kx x = 0.0125 m this is correct per submission.
Then substituted all values into Hookes law and got energy = .0281 J This was wrong according to submission.

If the elastic energy is a measure of the potential energy, how do I find that?
 
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Your formula for energy should work. Did you properly convert the units?
 
Yes I converted th distance x of 1.25 cm to .0125 m. The constant is 360 kN/m . Wait..do I need to convert the constant to N/m?
Which then makes the answer -.0281 KJ or -28.1 joules, correct?
 
Last edited:
dvolpe said:
Yes I converted th distance x of 1.25 cm to .0125 m. The constant is 360 kN/m . Wait..do I need to convert the constant to N/m?
Which then makes the answer -.0281 KJ or -28.1 joules, correct?


Yes. However your answer would be positive and not negative.
 

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