Answer
The arrows indicate the direction of motion.
Work Step by Step
Since $x=\pi t$, we have $t=\frac{x}{\pi }$. Substituting $t$ into $y$ gives
$y=sin\frac{x}{\pi}$.
This is a sine curve.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.