1 January 2022
Have you ever thought about what it would take for pitchers to throw a rise ball? Is it even possible? The rise ball myth in baseball has been debunked by most to be just that—a myth. Having analyzed the “apparent rise” or “what looks like a rise,” baseball analysts have described the phenomenon to be busted. However, that’s not all that there is to it.
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For instance, Alan Nathan, a physics professor since 1977, agrees that a fastball could rise in principle. He says that the ball could rise if pitchers gave it enough spin. But what remains to be seen is how much spin is required to achieve this feat. However, we’ll need to dive into a bit of physics to get some correct answers.
Let’s dive into some physics.
In simple terms, two forces act vertically on a pitch. The first force is pretty easy to understand, and it’s the force of gravity pulling the ball towards the ground. This force is affected by the ball’s weight and was established by MLB.
For this article, we’ll use 5 and ⅛ ounces equal to 0.32lbs, which translates to the downward force acting on the pitched ball. Now that that’s established, it’s time we move to the upward force that acts on a pitched ball, which is more complicated.
The Magnus Force
The upward force acting on a pitched ball is known as “lift” or the “Magnus force.” The Magnus force comes about through the action of the ball spinning through the air (a fluid). Thus, the spin and its intensity determine the amount of and direction of the ball.
The Magnus force is denoted as Cl, which stands for lift coefficient. In this scenario, r is the air density. At the same time, A represents the ball’s cross-sectional area, w represents the ball’s backspin in revolutions/minute, and v represents the ball’s speed in mph.
All these other quantities are easy to understand, and they play a massive role in helping us know more about the lift coefficient, i.e., the pitched ball’s rise.
While we won’t dive in too deeply about the exact equation used to determine the lift coefficient, we’ll provide a little more detail and an equation on how to figure it out. For more information, you could read Allan Nathan’s “The Effect of Spin on the Flight of a Baseball” for more information.
In summary, the Magnus force’s size depends on the ball’s speed and backspin in relation to its weight and air density. In other words, if the force acting on the ball’s downward weight is lower than the magnum force, then the ball will achieve a rise when pitched. Otherwise, the ball will fall towards the earth. This information is represented in the graph below.
In layman’s terms, any object that travels through the air has to act so that it creates lift, which is the force that makes it go upward. For instance, when airplanes move through the air, they do so at such speed and aerodynamic capacity that air under the wings forces the craft upwards.
In our case, the pitched ball’s backward spin could (theoretically) push the ball in an upward direction. For instance, when pitched fast enough and given enough backspin, the ball interacts with the air as an object would with water. The spin causes the air to be viscous enough to create and maintain the ball’s upward motion.
How fast does the ball have to be pitched?
The fastest pitch was over 104mph (courtesy of Aroldis Chapman). Assuming that the ball had enough backspin (2500rpm) to create continuous lift and that the ball traveled at a constant 104mph, the ball was still approximately ten mph away from making a rise.
Two problems could prevent even the fastest pitchers from throwing a rise ball. The ball loses speed by about eight mph and its rpm during its flight. Thus, Aroldis Chapman will have to maintain the ball’s speed at 113mph (or more) at 2500rpm or create more backspin.
You could use other options to increase the chances of creating a rise ball; however, these are beyond human capabilities. As such, it’s nearly impossible (at least for now) to pitch a rise ball, but it’s still a nice thing to think about.