Eli5 Coriolis effect


Suppose there is a disk rotating with a slider from the centre of the disk to the circumference ( radius of the disk ). Why is it that when the motion the slider is observed from a fixed frame at the side, the motion is shown to be curved? And from a rotating reference on top of the disk, the motion of the slider is straight. Isn’t it supposed to be the opposite? Or is the because of the slider? If so please explain how or why.

In: 3

I’m not sure I entirely understand, but here is my ELY5:

If the observer is rotating the same way the disk is, then there is no difference in movement between the two. For all the observer know, they could both be immobile and the slider is magically sliding to the top. So the movement is just a straight line.

If your observer is fixed, then in comparison the them the slider’s movement has two components: one that goes outward from the center, and one that follows the rotation of the disk. So from the observer’s POV that’s a curve.