Department of Mathematics, University of Sri Jayewardenepura
A procession (perahera) with fire-balls; Fire-balls with Mathematics. What…….?
You may aware that all fire-ball artists try to demonstrate circular motions using fire-balls. There are horizontal as well as vertical fire-ball displays. Whatever it is, main concern is to maintain a suitable speed to have a circle of fire.
Now, let us enter into Maths; . This is the basic equation that governs a circular motion. Here v – tangential velocity, – angular velocity and r – radius.
How can we catch up these terms from a fire-ball motion? Let us consider a motion of one fire-ball. If we keep our eyes with the fire-ball, the speed of rotating our eyes corresponds with w. Watch artist’s hands too! If w is high, hands are too quick. Now for v, keep your eyes in a particular point at the fire circle and try to tackle the speed of the fire-ball, when it is passing through that point. That speed is corresponding to v.
To display a fire circle, artists should maintain v appropriately in a higher value. Then relevant w is decided according to the length of the rope or stick that attaches the fire-ball. r represents this length. So, fire-ball artists are good users of Maths!
Why is that? Guess the trick with 
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