← Unit 3: Circular Motion and Gravitation
Centripetal Acceleration & Force
An object moving in a circle at constant speed still accelerates, because its direction is changing — this centripetal acceleration points toward the center of the circle.
Overview
Centripetal acceleration a_c = v²/r, always directed toward the center of the circular path. The net force causing this acceleration (F_c = mv²/r) is called centripetal force — it isn't a new, separate force, but rather whatever real force (tension, friction, gravity, normal force) happens to be supplying the center-pointing net force.
Practice Quiz
Question 1 of 1Score so far: 0/0
A satellite orbits Earth at radius r. If the orbital radius is doubled, what happens to the gravitational force between Earth and the satellite?