<PRE><B>Question 348808</B>
The blades on a model windmill take 4 seconds to make a full rotation. At the lowest point, the tip of the blade is 0.5m off the ground, and at the highest point the tip of the blade is 2.5m off the ground.
Question: Determine an algebraic equation relating the height(h) in metres of the tip of the blade above the ground at time(t) in seconds.
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Diameter of the fan: 5-2.5 = 2.5 m
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amplitude = (1/2)2.5m = 1.25m
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Period = (2pi)/b = 4 sec
b = 2pi/4
b = (1/2)pi
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Vertical shift is the distance of the center of the fan from the ground
= 2.5 + 1.25 = 3.75 meters
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Equation: y = 1.25*sin((1/2)pi*t) + 3.75
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{{{graph(400,300,-6.5,6.5,-10,10,1.25sin((1/2)(3.14)x)+3.75)}}}
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Cheers,
Stan H.</PRE>