Test your knowledge on spin and the Magnus effect

Types of Spin
There are 4 types of spin

Using the tennis ball experiment on the types of spin you can create

Types of Spin
topspin: eccentric force applied above centre of mass (spins downwards around the transverse axis)
backspin: eccentric force applied below centre of mass (spins upwards around the transverse axis)
sidespin hook: eccentric force applied right of the centre of mass (spin left around the longitudinal axis)
sidespin slice: eccentric force applied left of the centre of mass (spin right around the longitudinal axis)

This article reports that according to a new study, the human visual system just is not equipped to track the curved course of a fast-spinning ball. The study was conducted by Cathy Craig, a psychologist at Queen's University, Belfast, Ireland. She decided to test if experienced players could follow the trajectories of balls with side spin. She asked players to say whether balls would end up in the goal when they watched a virtual reality display that simulated shots with a spin of 600 revolutions per minute. Even professionals couldn't predict how the spin would influence the ball's trajectory.

Spin is created by applying a force that is off centre to the object being thrown (or kicked) at the point of release. The effects of spin are important in all ball sports and throwing events. The Magnus effect explains why the paths of balls deviate from normal flight path.

Magnus effect, generation of a sidewise force on a spinning cylindrical or spherical solid immersed in a fluid (liquid or gas) when there is relative motion between the spinning body and the fluid. Named after the German physicist and chemist H.G. Magnus, who first (1853) experimentally investigated the effect, it is responsible for the “curve” of a served tennis ball or a driven golf ball and affects the trajectory of a spinning artillery shell.
A spinning object moving through a fluid departs from its straight path because of pressure differences that develop in the fluid as a result of velocity changes induced by the spinning body. The Magnus effect is a particular manifestation of Bernoulli’s theorem: fluid pressure decreases at points where the speed of the fluid increases. In the case of a ball spinning through the air, the turning ball drags some of the air around with it. Viewed from the position of the ball, the air is rushing by on all sides. The drag of the side of the ball turning into the air (into the direction the ball is traveling) retards the airflow, whereas on the other side the drag speeds up the airflow. Greater pressure on the side where the airflow is slowed down forces the ball in the direction of the low-pressure region on the opposite side, where a relative increase in airflow occurs. See Bernoulli’s theorem; fluid mechanics.

Focuses on the fundamental principle behind the curved flight of any spinning ball known as Magnus effect. How the theory of Magnus effect works; Correlation between the Magnus force and the rate of the spin; Explanation for believing that the curveball was an optical illusion.

No less than four principles are used to explain the movement of objects such as golf balls as they travel through the air. Since air is considered a fluid, then fluid dynamics, or the characteristics of moving fluids or objects moving through them are described using a Reynold's number.

Measurements are presented of the Magnus force on a spinning baseball. The experiment utilizes a pitching machine to project the baseball horizontally, a high-speed motion analysis system to determine the initial velocity and angular velocity and to track the trajectory over 5 m of flight, and a ruler to measure the total distance traversed.