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I need some help.

The question is:

At the local swimming hole, a favourite trick is to run horizontally of a cliff that is 8.3m above the water. One diver runs off the edge of the cliff, tucks into a ball and rotates on the way down with an average angular speed of 1.6rev/s. Ignore air resistance and determine the number of revolutions she makes on the way down.

Now i've done it like this but the anser is wrong.........

∆Ө = 1.6rev[(2 pie rad) ÷ (1 revolution)] = 10.05 radians

Well, gravity pulls her down at 9.8m/s². So in the first second she will fall 9.8m.

She only needs to fall 8.3m to the water.

So 8.3m ÷ 9.8m = 0.85s

It will take her only 0.85s to reach the water.

And she makes 1.6rev/s.

So 1.6 ÷ 100 = 0.016

Then 0.016 x 85 = 1.36

Thus she will make 1.36 revolutions on her way down.

What am i missing?

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# Homework Help: Rotational Kinematics of Running

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