Photo caption: Basketball players making seemingly impossible shots and gravity defying jumps during March Madness are doing more than entertaining the millions of people who will tune in to watch them play, says Dr. Erik Hendrickson, a professor of physics at UW-Eau Claire. They're also giving fans a physics lesson. After all, every part of the sport — from dribbling to passing to shooting — depend on physics and the laws of motion. (Photo by Bill Hoepner)
When millions of people tune in this week for the start of the annual March Madness NCAA basketball extravaganza, they’ll watch as the country’s best college players make seemingly impossible shots, clutch free throws and gravity defying jumps.
A sporting event like no other, diehard basketball fans and people who know almost nothing about the sport will fill out brackets, then spend hours watching the games, many even sneaking away from work or class to see how they or their favorite teams are faring in their pools.
So, what does it take to be among those elite athletes who make March Madness so exciting that WalletHub says distracted workers cost businesses about $13.8 billion during the tournament?
Obviously, natural talent, years of practice and countless hours in the gym all matter.
But so does a basic understanding of things like force, gravity, projectile motion and air pressure — or more simply put, physics (with a bit of math thrown in), says Dr. Erik Hendrickson, professor of physics and chair of the University of Wisconsin-Eau Claire’s physics department.
Every part of the sport — from dribbling to passing to shooting — all depend on physics and the laws of motion, Hendrickson says. Physics even influenced the evolution of the basketball, including its design and the ideal amount of air in it, he says.
The professor took a few minutes to explain why applying physics principles to basketball can give you new insights into the sport as you watch this year’s March Madness games.
Why do basketball players appear to float in the air when they jump?
When players jump high into the air, they leave the ground at a high speed. As they rise, the force of gravity slows them down. Thus, they spend very little time near the ground, but spend more of their hang time higher up in the air. This makes it seem like they are floating. When LeBron James or Giannis Antetokounmpo are running down the court with the basketball and they leap from a point just past the free throw line and then slam dunk the ball, it makes it seem like they were floating, but they were just spending most of the hang time closer to the top of their trajectory.
How does backspin help a player make more baskets?
Having a nice backspin on the basketball when shooting doesn’t really affect the trajectory of the ball. So, it is not really the backspin that is helping the player make more baskets. Most players, though, will tell you that consistency is key in making your shots. If the ball rolls off your fingers the exact same way every time you shoot it (especially long-range shots, like 3-pointers), you get yourself into a rhythm of consistency (this is called muscle memory). If your hand placement on the ball tends to vary when shooting, there will be times when there is side spin on the ball. This is mostly an indication that you were not being consistent with your shot mechanics. When a defender attempts to block your shot, and you must make an adjustment in your release, many times the ball doesn’t have the same uniform backspin. These altered shots don’t go in as often. Instead of being consistent, they are relatively chaotic, which makes it difficult to practice and perfect. One last point: Backspin tends to create a “softer” bounce off the rim. This should limit those long rebounds that turn into transition baskets for your opponent.
Why do basketballs have bumpy dots?
The bumpy dots are for better grip on the ball, which provides more control when passing, dribbling and shooting. It even helps when the player’s hands are sweaty, versus a smooth ball. It turns out that there are about 35,000 dots on an NBA basketball (basketballword.com).
Why is it so hard to make a basket when you’re moving?
Again, this has to do with muscle memory and consistency. If you are standing still and you practice a shot from a particular distance over and over, when this situation presents itself in a game, your muscle memory kicks in, and it is easier to make the shot. When you are running at full speed and try to shoot, or if a defender is chasing you down and trying to block your shot, you are not standing still when you release the ball. It is harder to gauge how far you are from the basket, you and your body (and the ball) already are moving, so you don’t have to give the ball the same speed that you did when standing still. Trying to figure out how much more/less speed (or maybe if a different angle is needed) is difficult to do in the split second that you have to shoot the ball before the defender might block it. Of course, shooting a free throw should be the easiest basket to make (no defender, you are not moving), but then your mind takes over. The pressure/stress/fatigue can cause all that muscle memory to get thrown out the window. The NBA average for free throws is 73% (bleacherreport.com).
Why does a basketball need high air pressure?
The air pressure in a basketball determines how much it bounces when dribbled or when it hits the backboard/rim. Again, all the players want it to be consistent. Their muscle memory knows how hard they must push on the ball to dribble it, or to shoot it, or to pass it. If the pressure varied from ball to ball or game to game, they would lose this consistency. Handbooks will tell you that the ball must have a pressure between 7.5 and 8.5 psi to be used in an NBA game. Thus, it is possible for there to be too much pressure, as well as too little. Sometimes too much pressure will cause a ball to form large bumps on the ball, which will cause the ball to bounce erratically.
How can physics help you make more free throws?
The main way physics is used in free throws is to help players determine their preferred launch angle and launch speed. There are nearly an infinite number of possible launch angles that will allow the ball to go through the basket, but each of these angles comes with a specific launch speed. And these angles/speeds vary for players of different heights. Go back many years and you will find players who used a “granny shot” for their free throws. These usually had a very high arc on their trajectory. Since the ball is not that much smaller than the size of the basketball hoop, if you shoot the ball with very little arc, it is more difficult for the ball to go through the hoop (the player must be more precise in their launch angle/speed). The granny shot, with its high arc gives the shooter a wider range of possible launch angles/speeds where the ball will go through the hoop (the player doesn’t need to be as precise/consistent every time). Rick Barry, who shot underhanded free throws in the NBA, had a season average of over 90% seven different times in his career. The granny shot is still looked down upon by basically all players (college and pro) as not being “cool” enough. Shaq said he’d rather shoot 0% than shoot a granny shot.
