The Displacement from Equilibrium of an Oscillating Weight Suspended by a Spring

Multiple Choice

The displacement from equilibrium of an oscillating weight suspended by a spring is given by $y ( t ) = \frac { 1 } { 4 } \cos 6 t$ ,where y is the displacement (in feet) and t is the time (in seconds) .Find the displacements when $t = \frac { 1 } { 2 }$ .
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A) $y \left( \frac { 1 } { 2 } \right) \approx - 0.15$ foot
B) $y \left( \frac { 1 } { 2 } \right) \approx 0.15$ foot
C) $y \left( \frac { 1 } { 2 } \right) \approx - 0.05$ foot
D) $y \left( \frac { 1 } { 2 } \right) \approx 0.05$ foot
E) $y \left( \frac { 1 } { 2 } \right) \approx - 0.25$ foot