This experiment involves centripetal force, the force that keeps objects moving in a circular path. This force is perpendicular to the motion and directed towards the center of the circular orbit. By Newton's Second Law when a centripetal force acts on a mass (in a horizontal plane), the force continually changes the direction of the velocity without changing its magnitude, speed. This change in the direction of the velocity accounts for the centripetal acceleration of the mass, whose direction is towards the center. The relationship between the centripetal force, the mass of the orbiting object, and its speed and distance from the center is described by:
EXTENSION QUESTION: When twirling the mass, students found that despite their best efforts, they could not swing the ball so that the cord remained exactly horizontal.
(a) On the diagram of the rotating mass below, draw a force diagram of the forces acting on the mass and identify each force. Do not include any force components in this diagram.
(b) Explain why it is not possible for the ball to swing so that the cord remains exactly horizontal. Write your answer using complete sentence
