Verified answer

Assumptions:

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1 hp = 746 watts

g = 10ms⁻²

Now

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Energy = power x time = 8(746)15 = 89520J

this is the energy needed to lift junk metal in 15 seconds to a distance h;

Energy = mgh

h = 89520/(100 x 10) = 89.52m (293.7ft)

hp = (m)(g)(h) /(746 * t)

8 = (100)(9.81)(h) /(746 * 15)

h = 91.25m <=ans