Question

Whitney starts the engine on her small private airplane. The engine drives a propeller with a radius of 6.5 feet and its centerline 10.5 feet above the ground. At idle, the propeller rotates at a constant speed of approximately 850 revolutions per minute. The height of one propeller tip as a function of time is given by h = 10.5 + 6.5 sin(850t), where h is the height in feet and t is the time in minutes. Find h when t = 2 minutes
a. 4.1 ft
b. 9.4 ft
c. 16.9 ft
d. 11.6 ft

Answer 1

To calculate time at t= 2 minutes. We substitute at t = 2. 
h = 10.5 + 6.5 sin(850t) 
h = 10.5 + 6.5 sin (850 * 2) 
h = 10.5 - 6.4012 = 4.1 feet 
Hence at time t = 2, height = 4.1 feet.