# physics

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Draw the figure, and calcuate the height above the bottom point the swing starts. (I remember it as 2.3(1-cos25)).

the initial energy is mg*height.
The final energy is 1/2 m v^2

The difference is frction.

A 49 kg child on a 2.3 m long swing is released
from rest when the swing supports make an
angle of 25 degrees with the vertical.
The acceleration of gravity is 9.8 m=s2 :
If the speed of the child at the lowest po-
sition is 1.83818 m=s, what is the mechani-
cal energy dissipated by the various resistive
forces (e.g. friction, etc.)? Answer in units of
J.

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