A team of researchers at New York University has investigated the physics behind hula hooping, shedding new light on how a hoop stays aloft against gravity. Led by Leif Ristroph, the team conducted robotic experiments with hoops rotating around various shapes, including cones, cylinders, and hourglass forms.
Their findings reveal that successful hula hooping depends on two crucial conditions: synchronizing the hoop’s orbit with the body’s gyration and maintaining a stable, high-friction contact. The researchers discovered that an hourglass-shaped profile is essential for steady-state hula hooping, as it provides the necessary “waist” to support the hoop.
The team also developed dynamical models to analyze the motion of the hoop and body in relation to contact forces. These findings can be applied to various robotic applications, such as transforming motions, extracting energy from vibrations, and controlling objects without gripping.
Ristroph notes that their research was surprising, given the popularity and perceived simplicity of hula hooping. However, the researchers’ insights highlight the subtlety of the underlying physics, which could inspire engineering innovations and improvements in industrial processing and manufacturing.
Source: https://physicsworld.com/a/defying-gravity-insights-into-hula-hoop-levitation