(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

http://online.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys211/oldexams/exam3/fa08/fig10.gif [Broken]

A spool of mass M = 1 kg sits on a frictionless horizontal surface. A thread wound around the spool is pulled with a force T = 4 N as shown below. The total moment of inertia about the center of mass of the spool is I = 0.8 kg·m2, its outer radius is R = 1 m and its inner radius is r = 0.5 m. The spool starts from rest.

When the center-of-mass of the spool has traveled 2 m,

the net work done on the spool is 8 J.

(True/False Question)

2. Relevant equations

3. The attempt at a solution

I simply thought the net work done here is only by the tension force..

And i vaguely remember that the force given to the center of mass or the outer part of the edge would have the same acceleration "Acm".(Not sure if it's correct)

So i used the given tension 4N and into 2 meters which gives me 8J.

But it turns out that the answer is FALSE...

What's wrong in my thought?

Could someone help me out here....?

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# Homework Help: Rotational Kinematics of a spool of mass

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