The position of a 2.0-kg mass connected to a spring whose constant is 15 N/m is given by $x = A \cos ( \omega t - \delta )$ , where A = 25 cm and $\delta$= $\pi$/2. The potential energy of the mass at time t = 0 is
A) 0 J.
B) 0.47 J.
C) 0.50 J.
D) 1.0 J.

Question

The position of a 2.0-kg mass connected to a spring whose constant is 15 N/m is given by $x = A \cos ( \omega t - \delta )$ , where A = 25 cm and $\delta$=  $\pi$/2. The potential energy of the mass at time t = 0 is
A) 0 J.
B) 0.47 J.
C) 0.50 J.
D) 1.0 J.

Quizplus · Accepted Answer

At time t = 0, the position x = A $\cos(\omega \cdot 0 - \pi/2)$ = A $\cos(-\pi/2)$ = 0. Therefore, the potential energy, which is $\frac{1}{2} k x^2$, is 0 J.

The Position of a 2 x=Acos⁡(ωt−δ)x = A \cos ( \omega t - \delta )x=Acos(ωt−δ)

The Position of a 2 $x = A \cos ( \omega t - \delta )$