On the surface, longboarding may seem like a simple sport, but this assumption is misleading. At its most basic, a longboard is made up of a piece of wood, four wheels, and the trucks (pieces of metal) that hold the board and wheels together (Check out our whole post on the nitty-gritty of longboard design!). But far from basic, longboarding is a scientifically extreme sport involving the relationship between the physical components of the longboard (trucks, wheels, bearings, etc.), the skill of the rider, and the forces of the entire physical universe!
Longboards are technically just a subset of skateboards and usually have a range of length from 22 inches to 46+ inches, depending on the riders’ preferences (Looking for a guide on how to buy a longboard, skateboarder gift for your skater? Click here!). While a regular skateboard allows for freestyle and trick skating, traditional cruising is the preferred style for longboarders. But even without trick skating, there's plenty of science going on behind the scenes. Let's take a look!
Several factors go into understanding the physics behind any sport, and longboarding is no exception. If you remember anything about your high school physics class, you probably remember a dude named Isaac Newton and his three laws of motion. He states first that an object in motion and an object at rest will both remain that way in a perfect world without friction. Thankfully we live in a world full of objects that cause friction (like asphalt, and sidewalks) so that we can have the sport of longboarding! How does this work exactly? Your board starts rolling as you pump it. It would keep rolling forever and ever except that those friction-makers (like pavement) begin to slow it down. When you propel your longboard forward again, you restart the whole physics cycle. Don't you feel smarter already?
Mr. Newton's second law says that an object will accelerate (Speed! Sweet!) if the total force on the object is greater than its mass. Before we lose you with academics, lets put some real-world flesh on this idea. When you longboard downhill and speed up, this means that the forces acting on you and your board (gravity!) are more massive than what you weigh, so you start to move downhill! If you want to go even faster down the hill, we can hop back to Newton's first law, and you can crouch down to reduce your wind resistance (friction!). Without Newton's first and second laws, your downhill longboarding would be impossible!
Our man Newton has one more law of motion, his third, which says that every action creates an equal but opposite reaction. It seems ridiculous to think about, but did you know that when you place your foot down on the ground and push your longboard forward, that the earth is pushing right back up at you? Not only are you putting a force on the pavement, but the pavement is pushing that same force equally back at you! When you drag your foot to slow yourself down, the sidewalk is pulling you to a stop too. So next time you biff it on your board, don't be too mad at the ground. After all, you pushed on it first - it was just defending itself equally.
So we have been talking a lot about friction, but did you know that there are two types of friction that affect longboarders? Fluid (also known as Static) friction keeps an object still. When you set your board down on flat ground, and it stays put, this is an example of static friction. To start moving, you have to put enough force into your push to overcome the force of static friction. For an example of how much the forces of static friction can vary, think about how much harder it is to start your board on bumpy asphalt versus a seamless new sidewalk (Need ideas about where to longboard? Check our post about where to skate!). Dynamic (or kinetic) friction is similar, but instead of being that amount of force to *start* an object moving, its the amount of force needed to *keep* an object moving. You have to keep pumping your board to keep it moving; you have to keep up the force to make sure it overcomes the friction slowing it down.
Now wouldn't high school physics have been more fun if they used longboarding for all of the examples? We hope you've enjoyed this trip back to the (totally legit and rad) classroom for our study in the science of longboarding!