The Function $y = 1.6 \sin ( t - 1.8 )$

Multiple Choice

The function $y = 1.6 \sin ( t - 1.8 )$ models the displacement of an object moving in simple harmonic motion, where y is measured in inches and t in seconds. Find the frequency of motion

A) $\frac { 1 } { 2 \pi } \text { cycles per second }$
B) $1.6 \text { cycles per second }$
C) $1.8 \text { cycles per second }$
D) $2 \pi \text { cycles per second }$
E) $3.9 \text { cycles per second }$