How Do You Calculate Work and Force for a Displaced Mail Bag?

AI Thread Summary
To calculate the horizontal force needed to hold a displaced mail bag weighing 140 kg, the angle from the vertical is crucial, which is 22 degrees in this case. The correct tension in the rope should be recalculated, as the initial value of 1272 N was deemed incorrect. The horizontal force can be determined using the formula F = T * sin(θ), where T is the tension and θ is the angle. For work done, the formula W = F * d * cos(θ) applies, where d is the displacement. Accurate calculations will yield the correct answers for both the force and the work done.
melodrameric
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Hi there, I'm new here, and I desperately need help with this work/energy business. Here's my problem:

A mail bag with a mass of 140 kg is suspended by a vertical rope of length 8.00 m.
a) What horizontal force is necessary to hold the bag in a position displaced sideways a distance 3.00 m from its initial position?
b) How much work is done by the worker in moving the bag to this position?

I know that the angle from the vertical will be 22 degrees, and that the tension in the rope will be 1272 N (or am I wrong?), but I don't know where to go from there.

By the way, this is for a Mastering Physics problem, and I've already found out that 476.5 N [1272*cos(68)]is a wrong answer.

Thank you!
 
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You got the tension wrong, that's all. It looks like your method is OK.
 
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