Think this way: sin opposite hypotenuse, cos adjacent hypotenuse,

tan opposite adjacent

SOH CAH TOA

You have enough information to find theta (the angle).

-Andy

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- Apr 8th 2008, 03:50 PM #1

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## Swing Problem

A 16 kg child on a playground swing moves

with a speed of 9.5 m/s when the 2 m long swing is at its lowest point.

The acceleration of gravity is 9.81 m/s^2

What is the angle that the swing makes

with the vertical when the swing is at its

highest point? Answer in units of degrees.

For this problem, i solved for KE first. KE = 1/2mv^2, so plugging in some numbers I get 76 joules. Then I plug this into the PE equation (PE = mgh), so when 76 = (16kg)(9.81)(h) the height I get is .4841997m.

From this point on, I think I get stuck. I understand that energy is conserved, but how do I find out the angle that the swim makes? I tried using pythagorean's theorem, but that doesn't seem to work because the swing is always 2m long (which gives it a round opposite).

- Apr 8th 2008, 04:13 PM #2

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- Apr 8th 2008, 04:40 PM #3

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- Apr 8th 2008, 06:15 PM #4

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- Apr 8th 2008, 06:31 PM #5

- Apr 8th 2008, 06:37 PM #6

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- Apr 8th 2008, 06:46 PM #7

- Apr 8th 2008, 06:49 PM #8

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