The Physics of Baseball
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Bats

Player Photo There has been much controversy surrounding the types of bats. It is thought that corked bats give hitters more of an advantage, and that the reason college baseball players are able to hit the ball better and farther is because they use aluminum bats versus the wooden bats used by professional players. But does the type of bat really matter?

I. What are the differences between bats?

Bats have many characteristics that make them different, including their thickness and type of materials.

Wooden bats can even be further subdivided in what kind of wood was used to make the bat. Although most modern bats are made out of a mixture of hickory or ash, in the past bats were made only out of hickory.

II. Why is ash used?

Well, ash makes the bats lighter. But does a lighter bat mean better performance? The answer is yes and no. First let's examine the advantages of using a lighter bat.

Using common sense, the batter can swing a lighter bat faster than a heavier bat. If the batter can swing the bat faster, he/she has more time to decide what type of pitch he/she is facing. But how much additional time does the batter gain through a lighter bat?

Lets assume that the average time a ball travels from the pitcher's hand to the plate in about .46 seconds (assuming an average fastball travels 90mph and the distance between the plate and the pitcher's mound is 60'6''). If a bat's weight is reduced from 38 ounces to 32 ounces, the average time gained would be about 0.0133 seconds. By drilling a hole into the 32-ounce bat, thus reducing the weight by 1.5 ounces, the time gain would be 0.005 seconds. Does this time gain justify using a lighter bat? Only the hitter can decide for him/herself.

So will a corked bat help? Answer is probably no; players nowadays are using light bats anyway so there would be insignificant gain in the hitting performance and significant degradation in the range of a hit ball, making it easier for defense to catch the ball. Also there is a risk of getting caught. Corked bats are inheritantly weaker than standard bats, hence there is a greater chance that the bat will break showing the entire world what kind of player that person is. The last player who used a corked-bat and was caught (his batting average was arround .211, so you have to wonder if a corked bat actually works) got 11-days suspension and has to carry the stigma of being a cheater for the rest of his life.

III. Heavy bats

Why would anyone want to use a heavy bat? Some people use heavy bats because it can propel the ball further than lighter bats. When the bat hits the ball, it is also transferring some of its momentum into the ball. So the heavier the bat is, larger its momentum is, but only to a certain point. Look at the equation again, p = mv (momentum = mass*velocity). If the hitter can not swing fast enough (and thus decreasing the velocity), all the advantages of a heavier bat will disappear because the momentum will be less.

IV. Optimal bat weight

As you can see from above, the optimal bat weight will differ from person to person. According to Robert Adair, author of the book The Physics of Baseball, the optimal bat weight for Babe Ruth (weight: 251 lb) would have been 52 ounces, while Lloyd Waner (weight: 140 lb) would probably have wanted a 42-ounce bat.

V. Aluminum Bats

Aluminum bats are not allowed in the Major League but are widely popular in college and little leagues. College baseball is often derided for using aluminum bats and many say the bats are the reason college players hit better than they really could in the big leagues. Why do people use aluminum bats, and do they really offer players more advantages?

Usage of aluminum bats may be simple economics. Wooden bats are generally cheaper than aluminum bats, but they break more often. This can make them expensive over the long run to keep replacing. Aluminum bats, though they are more expensive and can still break, are much more durable and can be cheaper to maintain. So poorly-funded organizations (compared to the Major Leagues) will often opt for cheaper-to-buy-and-maintain aluminum bats.

What are other advantages of using aluminum bats? Well, since aluminum is harder than wood, manufacturers can vary weight distribution and shape with more ease compared to wooden bats. Also aluminum bats are harder/more inelastic than wooden bats of equal weight. What does that mean? Well, it means that the bat will sting less and less energy will be lost to rebound. Also aluminum bats have a larger sweet spot, making it easier for players to hit balls harder and more often. Aluminum bats give a greater advantage to the hitters with no strings attached.

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