The equation describing the position of an object undergoing simple harmonic motion is $x = ( 5.0 \mathrm {~cm} ) \cos ( 10 \pi t - \pi / 2 )$ , where t is in seconds. The phase constant at t = 0.20 seconds is
A) zero.
B) -$\pi$.
C) - $\pi$/2
D)-(3/2) $\pi$

Question

Quizplus · Accepted Answer

The phase constant in the equation of motion $x = A \cos(\omega t + \phi)$ is the term $\phi$, which is the phase of the motion at $t = 0$. In the given equation, $x = (5.0 \, \text{cm}) \cos(10\pi t - \pi/2)$, the phase constant is $-\pi/2$, which is option C when interpreted correctly from the placeholder text.

The Equation Describing the Position of an Object Undergoing Simple x=(5.0 cm)cos⁡(10πt−π/2)x = ( 5.0 \mathrm {~cm} ) \cos ( 10 \pi t - \pi / 2 )x=(5.0 cm)cos(10πt−π/2)

The Equation Describing the Position of an Object Undergoing Simple $x = ( 5.0 \mathrm {~cm} ) \cos ( 10 \pi t - \pi / 2 )$