Determine the Equation of the Graph $\frac { 1 } { 2 }$

Multiple Choice

Determine the equation of the graph.
-A weight attached to a spring is pulled down 6 inches below the equilibrium position. Assuming that the period of the system is $\frac { 1 } { 2 }$ second, determine a trigonometric model that gives the position of the weight at time $t$ seconds.

A) $s ( t ) = 6 \cos 4 \pi t$
B) $s ( t ) = - 6 \cos 4 \pi t$
C) $\mathrm { s } ( \mathrm { t } ) = 6 \cos \frac { 1 } { 2 } \mathrm { t }$
D) $s ( t ) = - 6 \cos 2 \pi t$