#### tony873004

Science Advisor

Gold Member

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a.) To what maximum vertical height (above the bottom of the swing) does the child rise, assuming he sits still and "coasts"?

m

b.) Reanswer part a, with the initial speed of the child being half as much.

m

c.) During this process, how much work is done by the tension in the rope?

J

I got part A and B using [tex]\Delta K = - \Delta U[/tex]

But for part C, [tex]W = \Delta K = \frac{1}{2}mv^2[/tex] and [tex]W = Fd[/tex] or [tex]W=mad[/tex]

But the mass of the child is not given? How can I compute the work? Unless this is a trick question and the rope is doing no work. But the rope is what is responsible for the child rising, otherwise the child would continue on a straight path parallel to the ground. So the rope is doing work, right?