kinetic energy and mass are proportional.

Answer:

directly

Explanation:

Step1: Recall kinetic - energy formula

The formula for kinetic energy is $K = \frac{1}{2}mv^{2}$, where $K$ is kinetic energy, $m$ is mass and $v$ is velocity. When velocity $v$ is constant, $K$ and $m$ have a direct - proportional relationship ($K\propto m$ as $K = (\frac{1}{2}v^{2})m$, and $\frac{1}{2}v^{2}$ is a non - zero constant when $v$ is fixed).