Mary starts at the edge of a circular platform that is slowly rotating on a frictionless axle. She then walks towards the opposite edge, passing through the platform center. Describe the motion of platform as Mary makes her trip. Explain the physics.

Explanation:

The motion of Mary along the circular path is a centripetal.

As Mary moves from one edge of the circular platform to the other edge, she is covering a distance which is the radius of the circular path at a velocity.

According to the relationship

w = v/r where

w is the angular velocity

r is the radius

v is the linear velocity

Initially, before Mary starts, her linear speed is zero and her angular velocity is also zero. As she move towards the opposite edge, she is covering a distance of radius r. According to the formula, increase in radius will leads to decrease in her angular velocity and vice versa. As Mary starts moving towards the centre of the circular path, her angular velocity increases, at the centre of the platform, her angular velocity is at maximum at this point. As she moves further from the center to the other edge, her angular velocity decreases due to increase in distance covered across the circular path.