Question

The question here explains how a pendulum can move in circular motion. I am aware that the central tenant of circular motion is that there is a centripetal force acting radially inward that takes on the formF=mv2rand that the velocity along this path is tangential to the object's path. The central force is the form taken on by the forces giving rise to circular motion. Thus, I see that if we state that a pendulum does exhibit circular motion, we can use Newton's second law to write force equations where the combination of tension and gravitational force collectively give rise to circular motion. However, I am unsure why it is valid to make the proposition that the pendulum does, in fact, exhibit circular motion. Is this motivated by physical observation?

Answer 1

The proposition that a pendulum exhibits circular motion is valid and motivated by physical observation. The torque applied at the center of mass, caused by the component of the object's weight tangent to the motion, creates circular motion.

Step-by-step explanation:

The proposition that a pendulum exhibits circular motion is valid and motivated by physical observation. When a physical pendulum is hanging from a point but is free to rotate, it rotates because of the torque applied at the center of mass, produced by the component of the object's weight that acts tangent to the motion of the center of mass. This torque causes the pendulum to move in a circular path.

The centripetal force responsible for maintaining this circular motion is provided by the tension in the string or the gravitational force, depending on the orientation of the pendulum. Newton's second law states that an object will accelerate in the same direction as the net force, and in the case of circular motion, the net force is directed towards the center of rotation.

Therefore, based on physical observations and the principles of Newton's laws of motion, it can be concluded that a pendulum exhibits circular motion.