Write trig equation for given word problem

Question

40-foot diameter Ferris wheel rotates at a speed of 2 revolutions per minute. Center pivot point of the

Ferris wheel is 25 feet above the ground. Assume rider start at the bottommost position. Find an

equation giving the height of the rider t seconds into ride

Answer 1

since you start at the low point, go up to maximum and then back down this would best conform to a -cosine graph

A is 20 radius of the ferris wheel

Period is 30seconds so B =2pi/30=pi/15

There is no phase shift so C=0

Vertical shift D is +25

So f(t)= -20cosine((pi/15)(t))+25