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Salk13
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Homework Statement
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A glass marble is dropped down an elevator shaft and hits a thick glass plate on top of an elevator that is descending at a speed of 2.10 m/s. The marble hits the glass plate 7.5 m below the point from which it was dropped. If the collision is elastic, how high will the marble rise, relative to the point from which it was dropped?
Homework Equations
v 2 - u 2 = 2gh
v 2 = u 2 + 2gh
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H = v 2 / 2g
H-h= required height
The Attempt at a Solution
[/B]v^2=(2.10 m/s)^2+ 2(9.81)(7.5m)
v= 12.31
12.31^2 / 2(9.81)
7.72-7.5= .22
not right answer though!