Some scientists believe that as stars evolve, they follow a certain pattern and undergo certain changes. Use reference materials for help in trying to find the relationship between a star’s position on the H-R diagram and its age.

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.