Aquila Children's Magazine AQUILA Magazine Best Bits | Page 36

Not the first venue that springs to mind Skateparks. A place to hang out with your friends at the weekends, right? Kit. The skatepark is where I go to when you think of maths and science, is it? (Nope, definitely not, carry on. Ed) get away from Harvey and Calculata when they send me into overload, but Did you know that your local skatepark is actually a great place to put mathematical theory – think calculus – into action? Accurately calculating your motion and velocity as well as understanding angles, circles and how to use your body’s centre of gravity, can make the difference between pulling off a trick perfectly, or falling on your…erm… mass. A NEED FOR SPEED (AND MOMENTUM) What’s the best way to pull off a trick? Too fast and you’ll fly off the end of your board and smack into a wall. Too slow and you’ll never build up enough energy to pull off a stunt or leap across a void. How can you even tell how fast someone is travelling? RAD REVOLUTIONS SPEED EXPERIMENT Set up a long tape and stand by with a stopwatch in your hand. Time how long it takes your friend to run or ride from the start of the tape to the end of the tape. Write down the length of the tape e.g. 30 metres and the time e.g. 9 seconds. To work out how fast they travelled, divide the distance by the time. When 12-year-old Tom Schaar landed the world’s first 1080 trick (that’s three full rotations in the air before landing) 30 metres ÷ 9 seconds = 3.33 m/s. That’s how fast they were travelling in metres per second, to convert it to miles per hour – times the answer by 2.24 (3.33 x 2.24 = 7.5 mph). in 2012, scientists Your turn – what will you discover about the speed of your skateboarding friends? Can they time you? What else can you observe? children have an advantage over adults and mathematicians were baffled. How had Tom been able to do it? Was his incredible success down to his size and weight? Do on performing such feats? Rhett Allain, an associate professor of physics, pondered these questions and figured out that bigger doesn’t always Momentum is the measure of mass in motion. Change in mass or velocity (speed) can change momentum. The formula is p = mv (p = momentum). Momentum = mass x velocity. Imagine you’re travelling on a skateboard at 20 m/s and you weigh 50 kg. You could calculate momentum as: 50 kg x 20 m/s = 1000 kg m/s. The momentum the rider builds up is transferred into the trick they pull. A successful use of momentum would be catching air on a ramp. A momentum fail would be crashing into the ramp, losing momentum and velocity and bruising your bottom. A skateboarder weighs 40 kg and travels at 20 m per second. What is their momentum? 800 kg m/s There is a mathematical formula for calculating speed. mean the same. By this, he meant that you can’t just use scale when comparing small with large – there are many variables that need to be taken into consideration and adjusted. Maybe if the first person to pull a 1440 is a 6-year-old, then we will be closer to knowing whether size does matter! There are 360 degrees in a circle. There are 180 degrees in a semicircle.