PLEASE PLEASE HELP A Ferris wheel moves with constant speed and completes one rotation every 40 seconds. The wheel has a radius of 12 m and its lowest point is 2 m above the ground. The height of a chair on the Ferris wheel above ground can be modelled by the function, h(t) = a cos bt + c, where t is the time in seconds.
a) Find the value of a, b and c.

The chair first reaches a height of 20 m above the ground after p seconds.

b) Find the angle that the chair has rotated through to reach this position.
c) Find the value of p.