A Ferris wheel with a radius of 13 m is rotating at a rate of one revolution every 2 minutes. How fast is a rider rising when the rider is 18 m above ground level?

Assume the center of ferris wheel is 13 m from ground

h = elevation of rider

A = angle of elevation of rider with respect to center of ferris wheel

dA/dt = 2pi/2 = pi rads/min

h = 13sin (A) + 13

dh/dt = 13cos (A) dA/dt

when h = 18 m

18 = 13sin (A) + 13

sin (A) = 5/13

cos (A) = sqrt (1 - (5/13) ^2)

cos (A) = 12/13

dh/dt = 13*12/13*pi

dh/dt = 12pi m/min