It's a neat piece of science art, and it also tells us something interesting. The arrows show us that the force on the skateboard is constantly changing, both in magnitude as well as in direction. Now the force of gravity obviously isn't changing, so the reason that these force arrows are shrinking and growing and tumbling around is that the skater is changing how their feet pushes and pulls against the board. By applying a variable force that changes both in strength and direction, they're steering the board.
The good news is that majority of skate shoes today come with high-quality flat soles that are capable of providing the maximum surface area designed to let you come in contact to the board, thereby promoting better control. Look for a really durable shoe, which you can wear comfortably to guarantee a safe and enjoyable experience when you are skateboarding.
Ohderii Skate Skateboards are made of a High-quality Plastic deck which will not easily break even when pressed over by a car. It comes with 3.125″ all aluminum alloy trucks, 59mm 78A super smooth PU wheels and ABEC-7 stainless steel bearings. It is ready to use and you can easily store it in your backpack. It has an average rating of 4.5 on Amazon.