Several particles are executing uniform circular motion. If all of...

The linear speed $v$ of a particle in uniform circular motion is related to its time period $T$ and radius $r$ by the formula:
$v = \dfrac{2\pi r}{T}$

Since the time period $T$ is constant for all particles, the term $\dfrac{2\pi}{T}$ is a constant.
Therefore, $v \propto r$.

The graph of a directly proportional relationship is a straight line passing through the origin.

Answer: A straight line passing through the origin