How is Work Calculated for Pulling Up a Curtain?

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The discussion focuses on calculating the work done to pull up a curtain with a length of 2 meters and a weight of 1 kg. The correct approach involves using the formula for work, A = F * s, where the force decreases linearly as the curtain is raised. The calculated work done is 9.81 J, based on lifting the center of mass of the curtain 1 meter. There was initial confusion regarding the mass, which was clarified to be 1 kg instead of 2 kg. The method used to arrive at the answer is validated as correct.
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Homework Statement



A curtain is rolled up a thin rod. There is no friction. The length of the curtain is l=2m and weight is m=2kg. Find the work done.

EDIT: the mass is 1kg not 2.

Homework Equations



A=Fs

The Attempt at a Solution


The solution is A=9.81J The way I did it was that the work done is the area under the curve on the F/s plot. Since the force needed to pull drops linearly, I simply multiplied mg*l and then I divided that by two. Is this approach valid? The answer is correct.
 
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mg*L/2 equals 19.6 J are you saying that 9.81 J is supposed to be the correct answer? I assumed that the center of mass of the curtain was at L= 1 m and that mass was lifted 1 meter to the top of the window. Work = Force * distance * Cos(0)
 
I mistyped the mass, it is 1kg.
 

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