In recent years, an acoustics professor and engineer, Daniel Russell, from Pennsylvania State University helped, Bat-Ball Science Mass Moment of Inertia article, The Science Behind Breaking Baseball Bats, Characterizing the performance of baseball bats, Performance versus moment of inertia of sporting implements. Otherwise, the effective mass of the bat is less than its whole mass. Edd Roush holds the distinction of being the heaviest Major League Baseball player in terms of weight. << There is a significant difference between end-load and balanced softball bats in terms of weight distribution. What are the physics of hitting a baseball? Published Mar 30, 2018 4:11 PM EDT. << Why dies the bat vibrate inside or outside of the sweet spot? As a result of the transfer of kinetic energy from the bat to the ball, it has increased mass and kinetic energy. At one point, called the node, the waves always cancel each other out. According to Science Daily, human hands are sensitive to vibration frequencies between 200-700 hertz and we experience the most pain when those frequencies are between 600-700 hertz. Popular Science 71.6K subscribers Subscribe 162 19K views 4 years ago Where is the sweet spot on a baseball bat and how do you find it? Every sport is governed by the laws of science physics, aerodynamics, kinematics, etc. Adding to that is the fact that bats have narrower handles than in the past which makes the bat less sturdy and more prone to breakage. But its not that simple. The results are very surprising. Join PopSci+ to read sciences greatest stories. Depending on how the ball rotates, the wake may deflect. Pitching Mechanics.- 6. The batter needs to exert a small couple to get the swing started, using equal and opposite forces on the handle, otherwise the barrel of the bat will get left behind. A great way to keep a rhythm throughout your swing is to step or stride toward the pitcher. External forces are the only way to redirect the ball according to the first law of motion. You can actually hear where the sweet spot is just by tapping a bat yourself. 3. This cookie is set by GDPR Cookie Consent plugin. If you drop the weight, you will be able to use the bat with greater control and power. According to Newtons third law, every action has an equal and opposite reaction. >> J,g]g+e/h_!_gCtO=0f)$P%cIi8Zdfc5&3j_8$7g. So, after a rainy day game, ensure your bat is dry before you store it. The batter exerts some 6000-8000 pounds of force on the ball. The three elements of a game of baseball are critical, and the game is built around Newtons laws of motion. /N 7 0 R /Title (Untitled) That should sound like more of a thud, because youre not hearing the vibrations inside the wood. 22 0 obj Demonstrating the sweet spot of the bat in a talk I gave at Wrigley Field for University of Illinois alumni in 1997. 12 0 obj There is enough physics in it to keep a PhD student busy for a few years. At room temperature, it will go from a solid to a gas directly. The ratio of ball speeds after and before colliding with the bat is called the is combined with the kinematic properties of the bat (determined from the moment-of-inertia of the bat and the impact location) to obtain the Bat-Ball Coefficient-of-Restitution, or BBCOR for the collosion. The majority of hitters take a stride when hitting, which helps the timing of their swing. /V 18 0 R When To Know Its Time To Replace Your Baseball Mitt, Customizing Your Baseball Bag: A Guide To Personalizing Your Equipment. The more general recommendation is that a teams best hitters should be grouped together in the batting order, rather than spread out, as this maximizes the chances of someone being on base when a good hitter comes to bat. As discussed earlier, missing the sweet spot can cause vibrations in the bat. Preliminary In order to indicate the origin of the baseball bats problem, the following preliminary are worth mentioning. Results for a baseball dropped from heights of 1, 5, 10 and 15 cm onto a piezo are shown below. What is velocity of bullet in the barrel? Metal bats, on the other hand, are lighter and more forgiving, but they lack the power of iron bats. << Learn how the sweet spot correlates with movement and vibration. The ball is spinning clockwise before it bounces and hits the granite block with backspin. 19 0 obj The bat breaks when large amplitude vibrations reach the thin part of the handle. If this is the case, the bats likely too heavy if it cant keep its grip in place for at least 20 seconds. Sniper Skin Announces Their Newest Partnership with Bassmaster Opens Pro, Briana Tucker! >> >> throughout the paper. It's where the wood grain is strongest. << endobj What two factors determine the location of a baseball bat sweet spot? The fundamental mode of a wood bat has a node located typically about 17 cm from each end and a frequency typically of about 170 Hz. Second, if players started using aluminum bats, every MLB record would be shattered within a year and the statistics of the game would be changed completely. The heavier the bat, the higher the bats bat speed. Try this: dangle the bat lightly by its knob, then use a baseball to strike the bat moving from top to bottom. << For a tennis racquet only the fundamental mode of vibration is excited by the impact since the impact duration, about 5 msec, is too long to excite higher frequency modes of the racquet. Are you a fan of composite or wood? For example, a 33-inch bat with a -3 rating weighs 30 ounces. Bud Hillerich, an apprentice woodworker in Louisville, Kentucky, began making Louisville Slugger bats in 1884. Players tend to feel a zing in their hands; often called bat sting. If the bat approaches a ball incident at speed vin then. << It is not quantum physics or relativity, but a very interesting problem involving the mechanics of colliding objects. For further details, see American Journal of Physics, September 1998 and also American Journal of Physics, 69, 231-232 (2001). The weight drop of a baseball bat is the difference between a bats length and its weight in ounces, which is the difference between a bats length and weight in ounces. The same thing happens when swinging a golf club, but it is not a well-known effect. This area is a product of physics, as the sweet spot is located at the center of percussion, which is the point on the bat that produces the least amount of vibration when hit. In principle you could also work out the acceleration due to gravity in Sydney, but not very accurately. Its moment of inertia about an axis through its center of mass is 0.184 kg.m^2. What have you found works for you? When a ball player hits the ball with the bat, it produces an enormous amount of force on the bat in a split second - the impact could mean up to 5,000 lbs of force. As a result, the bounce is relatively weak at the tip and near the center of mass. The mode shape of a baseball or softball bat is a simple flexing bending shape that has parts that move and parts that don't. Every bat has a point about seven inches in from the tip of the bat that doesn't move, that doesn't vibrate, called a node. Baseball bats have a sweet spot which is the ideal location on the bat to hit the ball for maximum performance. A high performance bat has a strong trampoline effect and hence a relatively large COR. The sweet spot of a baseball bat, like that of a tennis racket, can be defined either in terms of a vibration node or a centre of percussion. . This is not an easy rating to obtain. A paper on this subject can be downloaded. The swing weight of the bat (that is, its moment of inertia) can be determined from the measured period of oscillation when swung as a pendulum. If the ball is at rest (when striking a ball off a T ) then. listeners: [], 3. So, for the sake of the integrity of the game and safety, bats have remained wooden. Since F = m*dv/t, we can integrate the force waveform to measure ball speed vs time, then integrate v = dx/dt to measure the shift in the ball CM vs time. The result was not a super slow softball spin, neither was it particularly fast. So grab your bat and lets dive into the science behind the swing! /V 24 0 R Near the end of the swing, the batter needs to exert a large negative couple on the bat, otherwise the bat will swing around too fast and strike the ball when it is aligned at the wrong angle. @L`YKUJNGBP\poR=_;Dl'P(T /N 6 0 R dKoL!8Ka#EV,@V!\j8ZFbp6EE<9cn=N6j0nf;(&;QU6bUD')c@\ /V 16 0 R Some results for an Easton BK7 aluminum bat are shown below in 13 QuickTime movie files, each about 1 Mb. Mass has no effect on distance, but if you cant generate enough bat speed to overcome mass, you are doing yourself no favors and going backwards. The whole mass of the bat is not involved in the collision, unless the collision happens to occur at the centre of mass of the bat. The bat and the forearms are locked at right angles at the beginning of the swing, by locking the wrists, otherwise the bat would start to rotate in the wrong direction at the beginning of the swing. The ideal is the 110 turn model. Why? The tube wall is thinnest, stretchiest, and tapered before being rolled, and then the handle is formed. At any given time, the center of the circle can be found by fitting a circle to three neighboring points, at say time t, and at times t + 0.02 s and t - 0.02 s. This gives the radius, R, of the circle, from which we can calculate the centripetal force MV2/R as well as the force at right angles to that, given by M (dV/dt). In Section 4, we present a dynamical model to modeling the sweet spot on a baseball bat. %PDF-1.1 Also shown for comparison is a bounce off a heavy block of granite so that the COR of the ball can be determined. The pain of hitting away from the sweet spot motivates you to learn how to find itthat, or buy a composite bat with a vibration damper in the handle. endobj The impacts were at distances of 2, 7, 12, 17, 24 and 31 cm from the end of the barrel. In this article, well explore the various components that go into making a baseball bat, as well as how they work together to help a hitter put their best foot forward. Each impact was recorded on a video camera at 25 frames/sec. Regardless of age, the weight of the right handers bat is crucial. The 232 g bat was swung at 45 radians/sec on average (by the batter in the film). If you hit a baseball somewhere other than the sweet spot, your hands will feel the vibrations. /Length 996 The collision of a bat and a ball can be understood by treating the bat as a heavy ball whose mass depends on the impact point. It is not the actual weight that determines the swing speed but the swing weight (ie the moment of inertia). /N 24 0 R The experiment described below would be an ideal project on the physics of baseball, for any high school or University physics student. I simply wanted to know whether a hand launched ball spins at around 100 rpm or whether it could be as high as 1000 rpm. In any collision, energy from both objects gets transferred around, but in a swing your goal is to put as much energy as possible back into the baseball. /P 4 0 R Licensed under CC BY-SA 2.0, via Flickr Creative Commons. Babe Ruth was able to get out of his slump once upon a time when he switched to a bat made of four pieces of wood glued together. A rough estimate would be that the ball rotates 1/4 revolution while it is in the pitchers hand, and while the hand moves forward say the last 0.2 m. If the hand moves forward at 10 m/s = 22.4 mph then it moves 0.2 m in 0.02 sec, so the spin rate would be 12.5 rev/s or 750 rpm. So, if you make sure the label is up, it means that you will be making contact with the edge of the grain which is the strongest part. The effect of the hands on the centre of percussion is described in American Journal of Physics, , 622-630 (2004). /R [52 73 308 791 ] Reflexes. /P 17 0 R When a player has a bad hit and fails to hit the sweet spot, it causes vibrations which can cause the bat to bend or break. The ball bounces while it is still compressed, and recovers to its original sherical shape after it bounces. How do you control where to hit a baseball? /P 4 0 R Potential energy is what might be called stored energy. The physics behind this phenomenon involves the transfer of energy from the bat to the ball. The COR for the impact on the granite block is about 0.59 in the low speed collision here, but can be as low as 0.45 in a 100 mph collision. More comparisons can be made by adding more information. >> A careful analysis of baseball dynamics shows that this special spot is located at the point where an applied force would result in pure rotation of the bat about the handle grip. endobj 1) Hit with the label up Manufacturers always place the label on the face of the grain. You can test your childs grip by having him or her hold the bat straight out in front of them, parallel to the ground, with their dominant hand. The sweet spot of a baseball bat, like that of a tennis racket, can be defined either in terms of a vibration node or a centre of percussion. The ball seems to spin faster when it is fresh and slower after it has been used, but more experiments are needed to determine whether this is in fact correct. /R [52 74 308 585 ] It would therefore not be surprising if a softball can be pitched at say 1000 rpm. It minimizes vibration of the bat and results in the maximum energy delivered to the ball, meaning it travels the farthest. The Sweet Science. Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. These modes are shown in the diagram above. If a player can maintain the same bat swing speed with a heavier bat, the heavier bat will produce higher batted ball velocity and an increase in distance. It is not easy to find information on the actual rate of spin of a softball in flight, but it is relatively easy to measure, at least at low ball speeds and low spin speeds. The vibration of the bat takes energy away from the ball. One was a 232 gram broomstick, one was a 871 gram Louisville Slugger wood bat with four holes drilled through the barrel, and one was the 871 gram bat increased to 1333 gram by inserting a steel bolt through each hole. >> The bat barrel initially bends backwards away from the ball while the handle bends outward and the vibration in the handle causes the players top hand to lose contact with the handle. The effect is known as the "trampoline effect". But the bat vibrates strongly for impacts near the tip of the bat and near its center of mass. So, using a heavier bat should result in faster hit balls, which means the hit ball will travel farther. The same batter swung the 871 g bat at 33 radians/sec on average, and he swung the 1333 g bat at 26 radians/sec on average. James Sherwood has a similar site http://m-5.eng.uml.edu/umlbrc describing test procedures used to certify baseball bats and balls at the University of Massachusetts Lowell. The size and weight of the bat is a matter of personal preference, but it is important to remember that a bat must be approved by the league in order to be used in official games. endobj The impact on a baseball bat is shorter (since the bat and ball are harder or stiffer), about 1 msec. /R [316 73 572 791 ] Join PopSci+ to read sciences greatest stories. The second you swing one, there is a certain romance to it. Any two connected segments can be analysed as a double pendulum. In general, swing weight increases with actual weight, but swing weight also depends on bat length and weight distribution. /N 16 0 R The same thing happens when swinging a golf club, but it is not a well-known effect. >> } The shapes of the force vs time curves are interesting since they tell us how the force on the ball varies with the amount of compression. >> I simply wanted to know whether a hand launched ball spins at around 100 rpm or whether it could be as high as 1000 rpm. It was found, by measuring the frequencies of lots of aluminum tubes (see photo). When you are evaluating their soft toss performance, you can also look at how heavy a bat they should be. Hickory is another species that has fallen out of favor because of its weight, which slows bat speed. At some point you will feel almost no vibration when you tap. Also shown for comparison is a bounce off a heavy block of granite so that the COR of the ball can be determined. This equation for acceleration can , Dry ice is the name for carbon dioxide in its solid state. However, it will also feel heavier when swung. To squarely hit a fastball, everything has to . Finally, if players started using bats made of a better material, the game would become dangerous as the baseball would start travelling much too fast. There's no stinging, no vibration and no broken bat. How much force does a baseball bat generate? This force is required to change a 5 1/8th-ounce ball from a speed of 90 mph to a speed of 110 mph, this distorts the baseball to half its original diameter and the bat is compressed one fiftieth of its size.. Rather, the physics depends more on the ratio of the bat and ball speeds, regardless of whether the actual speeds are around 1 mph or 100 mph. Movies showing the collision of a baseball with a cricket ball and the collision of two billiard balls are shown in the page on collisions. endobj There is a difference between a bat and a racquet here, in that tennis strings are very light and give back to the ball 95% of their stored elastic energy. The length, weight, and shape of the bat also affect its performance, as longer bats tend to have more power, and heavier bats tend to have more control. The cookies is used to store the user consent for the cookies in the category "Necessary". At other impact points, the impact is usually felt as a sting or jarring of the hands and forearm, particularly if the impact occurs at a point well removed from the sweet spot. Uncovering The Mystery Behind The Golden Glove Award What It Takes To Receive This Prestigious Honor, How To Restring A Rawlings Baseball Glove Web: A Step-by-Step Guide, Exploring The Meaning Behind The Phrase Peanut Butter Jelly With A Baseball Bat. Thats the sport that demands the most from the athletes who compete in it. This makes the game easier to pick up and more exciting to watch otherwise, every hit would only be a single. 6 0 obj The horizontal speed at the contact point depends on the rate at which the ball spins, as well as on the horizontal speed of the centre of mass of the ball. However, when the bat strikes the ball at the dead spot then the ball exit speed = V = speed of bat just before the collision. If the ball is also mounted as a pendulum, the experiment can also be performed in reverse, by swinging the bat at a stationary ball. The ball also generates potential energy through the bat, resulting in a powerful, far-reaching hit. Then can't we add to the list of deeper queries some of . /V 15 0 R A baseball bat is shaped in such a way to have a "sweet spot." The sweet spot is due to the fact that the CP and the VN coincide. Is it possible to hit heavier bats harder? The softball bat will vibrate mainly because it either hitting or missing the sweet spot. When you hit the sweet spot, the bat feels the best in your hand. 24 0 obj This is the online home for all things baseball. The weight of a bat can be calculated by subtracting the minus number from the length, which in this case is 33 minus -3, equaling 30 ounces. However, the COP shifts a long way toward the handle when a batter holds the handle, and plays only a minor role in the feel of the bat for an impact at the sweet spot. If the vibration frequency is less than about 1000 Hz, the end result is that ball comes off the bat at a lower speed than off a wood bat of the same weight and swing weight. Some of the numbers change with actual speed, but the physics doesnt change. << Though all of this means that us amateurs dont want to have batting practice for more than 10 minutes, it does help you train. endobj Theres one where it feels good in your hands, one where the ball comes off the fastest. The following three movies show a batter swinging three different bats as fast as possible, filmed at 25 frames/sec. >> The effect of the hands on the centre of percussion is described in American Journal of Physics, 72, 622-630 (2004). Step up to the batters box and get warmed up for the physics of baseball bats with this great video from ESPN Sports Science. Most people find that an impact between the nodes of the first two modes (node1 and node2 in the diagram) feels best since both modes are then excited only weakly. If you turn the volume up you will hear how the swing speed affects the sound of the swish through the air. /V 7 0 R Scientifically speaking, this is the weakest part of a wooden baseball bat. He has been writing about the sport for over five years and is passionate about sharing his knowledge and enthusiasm for the game. A ball that would travel 400 feet in "normal" conditions goes: 6 feet farther if the altitude is 1,000 feet higher 4 feet farther if the air is 10 degrees warmer 4 feet farther if the ball is 10 degrees warmer 4 feet farther if the barometer drops 1 inch of mercury 3 1/2 feet farther if the pitcher is . Largest thickness - The sweet spot Bat - Ball Collision Diagrams Vball 1 = Vb Vbat 1 = V2b V bat 2 = V2a Vball = V1a Before After Newton's third law says that for every action there is an equal and opposite reaction. This is why it is important that baseball bats are made out of a hard material that can maximize the energy transfer while also reducing the risk of injury to the player. endobj Adair provides a few answers in his book The Physics of Baseball but he does not give the directions or the torques. The tubes were suspended by a length of string so that they could vibrate for a long time without damping. Wind farms have different impacts on the environment compared to conventional power plants, but similar concerns exist over both the noise produced by the turbine blades and the . Upon impact with the ball, the rotation of the bat is reversed. /P 20 0 R A right-handed batter has an advantage in a sport where even the best hitters only succeed three times out of ten. One of the definitions of the "sweet spot" is the location of the node at the barrel end of the bat. Baseball bats are an integral part of the game of baseball, and their physics is an important aspect of the sport. However, it will also feel heavier when swung. A knob and end loaded bat may weigh the same, for instance, but the end loaded bat will have a higher MOI. /N 15 0 R Physics of Baseball & Softball R. Cross Published 22 February 2011 Physics, Education Preface.- 1. A similar question: The bumper on a pool table is at a height so that the pool ball does not skid when it hits it. These cookies will be stored in your browser only with your consent. Learn how to add this technique to your swing while still keeping a balanced, relaxed approach to the ball. George has always been passionate about physics and its ability to explain the fundamental workings of the universe. The sweet spot of a bat exists because bat vibrations are not excited significantly at that spot. Aluminum bats are hollow so the distribution of mass is very different than a wooden bat, which makes it much easier to swing the bat and therefore produces higher speeds and more powerful hits. << Registration on or use of this site constitutes acceptance of our Terms of Service. ] So, why does the MLB still use wooden bats? . /R [316 73 572 791 ] By clicking Accept, you consent to the use of ALL the cookies. Adding to that is the fact that, When a ball player hits the ball with the bat, it produces an enormous amount of force on the bat in a split second the impact could mean up to. However, the centripetal force does not act along the axis of the bat, but at an angle, as shown by the orange lines. The average hitter needs about 50 milliseconds to instinctively assess the speed and location of an incoming pitch. Learn How To Personalize Your Hat With Vinyl Stickers! endobj Impact towards the taper region of the bat causes to bat to bend backward in the middle, and sends a vibration pulse down the handle. Hitting the "sweet spot" is something that baseball players strive for. Except, of course, when you hit the sweet spot. If you hit . endobj The physics of baseball Baseball players know from experience that there is a ``sweet spot'' on a baseball bat, about 17cm from the end of the barrel, where the shock of impact with the ball, as felt by the hands, is minimized. This is due to the fact that the collision is able to create a larger transfer of energy when the bat and ball are in perfect alignment. He received his Ph.D. in physics from the University of California, Berkeley, where he conducted research on particle physics and cosmology. Here you'll find information on the game of baseball, from the rules to the history. Why? The ball rotated more than 1/4 but less than 1/2 of one revolution from one frame to the next, each frame being 0.04 sec apart. A bat with an end loaded weight indicates that it weighs between 30 and 28 ounces. Its harder than football, harder than baseball, harder than basketball, harder than hockey or soccer or cycling or skiing or fishing or billiards or any other of the 60 sports we rated. In fact, if the ball strikes the bat exactly on the ``sweet spot'' then the hitter is almost unaware of the collision. According to one study, Brazils free-tailed bats have the fastest flight speeds ever documented by flying at 160 kilometers per hour in flight. When the ball hits the sweet spot of the bat, the hand-held end of the bat should come to halt without receiving any impulse from the hand. 21 0 obj Maple bats are the most durable and have a larger sweet spot, making them ideal for power hitters. Not hitting the ball with the sweet spot of the bat causes more vibrations, which causes the sting for the batter. Explains that a baseball bat's "sweet spot" is approximately 17 cm from the end of the . The node sweet spot differs from the center of percussion sweet spot. Similarly, an impact at the node of the second mode will not excite the second mode but it will excite the fundamental mode. Baseball players obsession with bats is second nature to them. In practice, batters tend to prefer bats that are lighter, rather than more powerful, since lighter bats are easier to swing and make it easier for the batter to connect with the ball. Sara Chodosh The frequency is typically between 1000 Hz and 2500 Hz, meaning that the wall vibrates in and out 1000 to 2500 times in one second. You can tell the bat is too heavy if the player appears to be chopping at the ball. 1 inch in length is huge. We and our partners use cookies to Store and/or access information on a device. endobj Magnetism is also an important aspect of baseball because bats use magnetite, a magnetic substance found in the body, as a means of internal navigation. The spot is close to the centre of percussion (COP) for a freely supported bat, so it was thought at one time that the sweet spot might be associated with the COP.