A Mass on a Smooth Tabletop Is Attached to a Spring

Multiple Choice

A mass on a smooth tabletop is attached to a spring, as shown in the figure. The coordinate system has been chosen so that the equilibrium position of the mass corresponds to $$s = 0$$ . Assume that the simple harmonic motion is described by the equation $$s = 5 \cos \left( \frac { \pi t } { 3 } \right)$$ , where s is in centimeters and t is in seconds. Determine which table describes the s-coordinate of the mass at each of the following times: $$t =$$ 0 sec, 0.5 sec, 1 sec, and 2 sec. (One of these coordinates will involve a radical sign; for this case, use a calculator and round the final answer to two decimal places.)

A) $$\begin{array} { | c | c | } \hline \text { time (sec) } & \text { s-coordinate(cm) } \\\hline 0 & 5 \\\hline 0.5 & 4.33 \\\hline 1 & 2.5 \\\hline 2 & 2.5 \\\hline\end{array}$$
B) $$\begin{array} { | c | c | } \hline \text { time (sec) } & \text { s-coordinate(cm) } \\\hline 0 & - 2.5 \\\hline 0.5 & 4.33 \\\hline 1 & 2.5 \\\hline 2 & 5 \\\hline\end{array}$$
C) $$\begin{array} { | c | c | } \hline \text { time (sec) } & \text { s-coordinate(cm) } \\\hline 0 & 5 \\\hline 0.5 & 4.33 \\\hline 1 & 2.5 \\\hline 2 & - 2.5 \\\hline\end{array}$$
D) $$\begin{array} { | c | c | } \hline \text { time (sec) } & \text { s-coordinate(cm) } \\\hline 0 & 2.5 \\\hline 0.5 & 4.33 \\\hline 1 & 5 \\\hline 2 & - 2.5 \\\hline\end{array}$$
E) $$\begin{array} { | c | c | } \hline \text { time (sec) } & \text { s-coordinate(cm) } \\\hline 0 & 5 \\\hline 0.5 & 2.5 \\\hline 1 & 4.33 \\\hline 2 & - 2.5 \\\hline\end{array}$$