Advanced Functions
posted by  .
The vertical position, h, in metres, of a gondola on a Ferris wheel is modelled using the function
h = 10 sin ((pi/15) (td)) + 12
where t is the time, in seconds. The gondola must assume a vertical position of 7 m at t=0 s , and be on its way upward.
Determine the phase shift required for the desired operation of the Ferris wheel.

So we want h=7 when t=0 or
7 = 10sin((pi/15)(d)) + 12
.5 = sin((pi/15)(d))
the reference angle is pi/6 .... ( sinpi/6 = 0.5)
so (pi/15)d = pi + pi/6 or 2pi  pi/6 or pi/6
if we let (pi/15)d = pi/6
d = 5/2
so h = 10 sin ((pi/15) (t5/2)) + 12
check:
when t = 0, h = 10sin((pi/15)(5/2) + 12
= 7
t = .01
h = 7.018 , a bit higher , so it is on its way upwards.