To illustrate the relationship between kinetic energy and the mass of an object, a scatter plot would be the most appropriate choice.
A scatter plot allows you to show the relationship between two continuous variables: kinetic energy and mass. Each point on the graph would represent a specific mass and its corresponding kinetic energy, allowing you to visualize any correlation between the two variables.
A line graph might also be useful if you want to show trends over a range of values, but for depicting the specific relationship between kinetic energy (which is calculated as \( KE = \frac{1}{2} mv^2 \)) and mass, a scatter plot effectively shows how kinetic energy changes with different masses, especially when velocity is held constant.