The graph of the relationship between an object's mass and its kinetic energy (assuming constant velocity) would be a straight line that is directly proportional. The x-axis would represent the object's mass, and the y-axis would represent its kinetic energy. As mass increases, kinetic energy would also increase, and vice versa. So, the best graph for this relationship would be a straight line that starts from the origin and goes upwards at a 45-degree angle (slope of 1).
