A student runs at constant speed. But since it's happening on a circular track, we have to say that the student IS accelerating.
"Acceleration" DOES NOT mean 'speeding up'.
"Acceleration" means ANY change in speed OR direction of motion. Speeding up, slowing down, and curving or turning are all "acceleration".
On the circular track, the student's direction is constantly changing. So she is definitely accelerating.
