(II) Recall from Chapter 4, Example 4-14, that you can use a pulley and ropes to decrease the force needed to raise a heavy load (see Fig. 6-37). But for every meter the load is raised, how much rope must be pulled up? Account for this, using energy concepts.
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The work done by the person pulling must be equal to the work done on the piano. From the figure we have:
If the load is raised by 1 m the displacement of the rope will be x.
The work done is:
For every 2m of rope that is pulled up, the load rises by 1 m.