The Physics of Baseball—Nature Rules in All Hits: Part I

Posted on December 27, 2011 by admin

Gravity, drag force, Magnus force, inertia, gyradius…even baseball is subject to the laws of physics. Here’s a look at the universal rules underlying successfully hitting a baseball:

Gravity is, of course, the force of attraction by which terrestrial bodies tend to fall toward the center of the earth. The second a baseball leaves a pitcher’s hand, it’s headed to the ground.
Drag force is the force of air friction for a falling body, and it increases with speed. A falling object will reach a speed at which the force of air friction will be equal to and opposite the force of gravity. At that point, the object will no longer accelerate. Its speed will remain constant, and that speed (and direction) is called its terminal velocity. In fluid dynamics, an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid (in the case of a baseball–air) through which it is moving.
The Magnus force, after the German physicist Heinrich Magnus, who first described it in 1853–is the dominant spin-dependent force acting on baseballs. Backspin creates an invisible Magnus force underneath the ball that propels it upwards and outwards, making the ball work for us and NOT the other way around.
Inertia – the property of matter by which it retains its state of rest or its velocity along a straight line so long as it is not acted upon by an external force. As a measure of how lazy “stuff” is, inertia is the resistance of an object to a change in its state of motion.
Gyradius (or “radius of gyration”) is the name of several related measures of the size of an object (e.g., a baseball or a baseball bat), a surface, or an ensemble of points. It is calculated as the root mean square distance of the objects’ parts from either its center of gravity or an axis.

See Part II for explanations and view the video The Science Channel Videos: The Physics of Baseball: Hitting.

And use the Hitting Jack-It™ – Swing the System!