Question

The height of the tip of an airplane propeller above the ground once
the airplane reaches full speed can be modelled by a sine function. At
full speed, the propeller makes 200 revolutions per second. At t=0
the tip of the propeller is at its minimum height above the ground.
Determine whether the instantaneous rate of change in height at t = 1/300
is a negative value, a positive value, or zero.

Answer 1

\[\omega=2\pi*200=400\pi rad/s\]
\[h(t)=\sin(400 \pi t-\frac{ \pi }{ 2 })\]
\[h'(t)=400\pi \cos(400 pit-\frac{ \pi }{ 2 })\]
when t=1/300, you calculate the value of h'(t) and you¡ll get your answer