Question

A waterwheel with a radius of 10 feet is positioned so that its center is 8 feet above the water.

The waterwheel rotates at 5 revolutions per minute. You start your stopwatch. Two seconds later, Point P on the rim is at its lowest point. Assume that y varies sinusoidally with t, where y is the distance of point P from the surface of the water in terms of the number of + seconds that the stopwatch reads.
A. Write an equation: y=
B. Predict the distance from the surface of the water when the stopwatch reads 17.2 seconds
C. At 40 seconds is the point on the wheel going into the water or coming out?

Answer 1

A. y = 8 - 10sin(5πt)

B. y = 8 - 10sin(5π(17.2)) = 8 - 10sin(86π) ≈ 8 - 10(-0.99) ≈ 18.9

C. At 40 seconds, the point on the wheel is coming out of the water.