☰ button brings up a control panel
Animation on the left shows a small particle's motion on a smooth disc rotating with a constant angular velocity. The particle is initially located at some distance from the center of the disc and is moving with the disc. At some moment the rigid support holding it to the center breaks and the the particle starts sliding on the surface. The position of the particle on the disc at a given moment is marked as it slides on the surface of the disc.
On the right, the motion relative to disc is shown. The green vector defines the position of the particle.