home

The Physics of the Baseball Swing


**There are so many different aspects to hitting the ball in the game of baseball. The physics are seemingly endless. There is the homerun, which requires more power and backspin, then there is just the simple basehit. To the right, there is Ken Griffey Jr. who has arguably one of the best swings in the history of the game. He is a big guy, which also brings out another question, does it matter how big you are and how strong you are to hit homeruns? Griffey Jr. is a future Hall of Famer and is in the top 10 of the All-Time homerun list. Throughout this presentation, we will explore more questions concerning the physics of the very complex baseball swing.**

As the pitcher releases the ball, and the batter sees the ball approaching him, he automatically shifts his weight to his back leg and then back to his front, which is commonly called, "stepping into the pitch." Then the batter begins his swing by twisting his body and transferring considerable enegy into the ball by the bat. The hands and the bat initially move at around 40 mph. However, when the bat meets the ball, the hands and bat will move in excess of 70 mph. Because of this high speed, it only takes roughly 1/100th of a second to make a difference whether it is a homerun or a popup. In conclusion, we can conclude that the baseball is a very precise tool.



 ﻿The position a hitter holds the bat also plays a role in hitting. Hitting at the end of the bat

not only creates more power but also generates a longer arc in the swing. This longer arc

generates alot more power, we can conclude this in the equation:


 * VELOCITY=ANGULAR VELOCITY*RADIUS **

This equation tells us that the overall velocity is equal to the angular velocity, or the

velocity of the swing times the radius of the arc.

If hitters use longer arcs, less precision time is needed, however, the batter will also now

have to commit to the pitch early. Typically the long arc swingers, are the ones who will

hit the most homeruns, when the ones who decide to use short precise swings by holding

the bat higher up are the ones who hit for contact, because swinging with a smaller arc

can determine the type of pitch quicker resulting in a quicker swing and more contact.



﻿So what happens when the ball meets the bat? Well, say the pitcher is throwing a 90 mph fastball. At this speed, the ball will reach homeplate in approximately .4 seconds, which gives the batter roughly .2 seconds to decide whether to swing or not at the pitch, because the rest of the .4 seconds has to be dedicated to the actual swing, which will require around .15 seconds. If the batter doesnt read the pitch correctly by only 1.5 mph, his swing could be off by as much as a foot, early or late. And because the bat is only 2-3 inches thick, this misjudgement would result in missing the baseball. When contact occurs between the 90 mph fastball and the 70 mph swing, there is a very very powerful force created. The relative speed of this collision is 160 mph, so therefore, the baseball turned from kinetic energy as it was traveling towards the bat, and then switched to potential energy as it made contact and then switched back to kinetic energy. So what exactly happened here?

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%;"> <span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">The bat acts a spring. The baseball makes contacts with the bat, and compresses against it, then

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">it changes direction and transforms back into its original shape. The forces acting on the baseball

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">are between 6,000-10,000 lbs and typically occurs in 1/1000th of a second. This is why the average

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">baseball must be replaced after a while, because it becomes deformed from the violent collision.

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">Vibrations, are resulted from the area of the bat in which makes contact with the ball. However, the

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">sweet spot of the bat will cause no vibrations. The sweet spot is located about 17 cm from the end

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">of the barrel and when contact is made between the baseball and the sweet spot, the batter may not

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">even feel the impact. However, when the batter makes contact with any other part of the bat, there

<span style="background-color: #00ff00; color: #800080; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow: hidden;">is typically a stinging sensation.

<span style="background-color: #00ffff; color: #ff0000; font-family: 'Arial Black',Gadget,sans-serif; font-size: 110%; line-height: 0px; overflow-x: hidden; overflow-y: hidden;">

<span style="background-color: #ffff00; color: #000080; font-family: Impact,Charcoal,sans-serif; font-size: 110%;">IF YOU WANT TO SEE A BEAUTIFUL SWING, CHECK THIS SLOW-MO VIDEO OF JOSH HAMILTON, BEAUTIFUL.

<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/hl4rZ2Jtc3c" frameborder="0" allowfullscreen>

I ﻿ So Im sure this is what youve been looking forward to learning about. It is now time to discuss the physics of the HOMERUN!!.

The collision that occurs between ball and bat has alot to do with where and how far the ball travels. The ball and bat both have initial velocities before contact, and after contact, both have positive velocities. The physical relationship between the bat and ball in this instance is known as the law of conservation of linear momentum. Linear momentum is the product of mass and velocity of the objects. **p=mv.** While the bat and ball are in contact the player is exerting a force on the bat; the force needed to swing the bat.momentum is not constant because of this force exerted by the player swinging the bat. However, the force on the bat by the player is very much smaller than the forces between the bat and ball during the collision, and the contact time between ball and bat is very short (less than 1 millisecond). This allows us to ignore the force on the bat by the player during the collision between ball and bat without significantly affecting our results. If we ignore the force by the player on the bat, we can express the conservation of linear momentum by setting the total momentum before the collision equal to the total momentum after the collision.
 * //m//1//v//1b + //m//2//v//2b = //m//1//v//1a + //m//2//v//2a **

<span style="background-color: #c0c0c0; color: #000080; font-family: 'Lucida Console',Monaco,monospace;">During the collision the ball undergoes a significant amount of compression, and damping forces convert much of the ball's initial kinetic energy into heat. The change in potential energy and work done by friction describe how much of the initial energy is lost during compression of the bat and ball. The manner in which these energies are related during the bat-ball collision is rather complicated. However, the effective relationship between the elastic properties of the ball and the relative velocities of bat and ball may be summarized in terms of the coefficient of restitution, (e) The equation: Basically, the home run is the end result of alot of things, including these equations, and also the natural factors can have an effect on the trajectory of a homerun. However, this is just about all I could find on the baseball swing. So why not play baseball? it is a great game that seems so simple. However, after researching the physics of the game itself, i have concluded that there is a lot of physics involved in the swing of a baseball bat. In order to be successful, you must use the quickness of your hands, and the power of your abdomen and legs to generate power in your swing. In conlcusion, we can also say you must rely on the sweet spot of the bat to generate a great amount of velocity from impact. However, in order to do this, you must get the bat through the zone quickly. This is why the baseball swing is so complex. <span style="background-color: #c0c0c0; color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 140%;">Some neat facts that contribute to a ball that has already been hit around 400 feet:
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 18px; line-height: 27px;">If the ball has 1000 feet of altitude, then the baseball will gain 7 feet.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; font-size: 18px; line-height: 27px;">For every 10 degrees in air temperature, the baseball will gain around 4 feet.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">For every 10 degrees of ball temperature, the baseball will travel an extra 4 feet.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">With every 1 mph of trailing wind, the baseball will travel an extra foot.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">At 30% humidity, the baseball will lose 30 feet on its trajectory.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">For every extra 5mph the pitcher throws the ball, the ball will travel an extra 5 feet.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">If the baseball is hit along the foul line it will travel an extra 11 feet.
 * <span style="color: #008080; font-family: 'Palatino Linotype','Book Antiqua',Palatino,serif; line-height: 27px;">And finally, an aluminum bat gives the ball a 30 foot distance increase.