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posted by  Anonymous on 11/7/2009 1:09:16 PM  |  status: Live  |  Earned Karma: 0

Work done by force

Course Textbook Chapter Problem Needs by
General Physics 978-0-07-334886-5 6 N/A 11/10/2009 at 1:00:00 PM
Question Details:
This is a homework problem to be submitted online. I believe I am doing everything right but it is saying incorrect because of the significant figures. Please help!

The first part of the question:
(a) If the length of the Achilles tendon increases 0.33 cm when the force exerted on it by the muscle increases from 3900 N to 4500 N, what is the "spring constant" of the tendon?
Your answer is correct. N/m

The Second Part:
(b) How much work is done by the muscle in stretching the tendon 0.33 cm as the force increases from 3900 N to 4500 N?
Your answer is incorrect. J

I calculated: W=1/2(181818N/m)(.0033M)
=0.989999

is four significant figures not right? or did I do something wrong in the calculations?

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posted by leettab on 11/7/2009 1:37:48 PM  |  status: Live
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Response Details:
For the second part

work is equal to some force applied through some distance

W = F*d

from part 1 the force is 600 N

we are assuming that the force is applied parallel to the direction of motion.

So the work done is W = 600 N *(0.0033 m) = 1.980 J
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