Grand Canyon tightrope walk: Funambulist Nik Wallenda traversed a 1,500-foot gorge near the Grand Canyon on a 2-inch-thick steel cable on Sunday, carrying with him a 43-lb. pole. Why did he bring such a heavy pole?
Tiffany Brown/Discovery Channel/AP
To help him complete his journey along a 1,400-foot-long, 2-inch-thick steel cable that had been stretched across the Little Colorado Gorge, Nik Wallenda, a seventh-generation member of the legendary Flying Wallendas family of acrobats, brought with him a cross necklace, a pair of thin-soled shoes, and a flexible, 30-foot-long, 43-pound pole.
The reasons for the devotional object and the footwear are obvious to most of us who watched Mr. Wallenda teeter over the river some 1,500 feet below, but what was that huge drooping pole for? And why did it have to be so heavy?
To help him keep his balance. To prevent their death-defying acts from becoming life-defying ones, high-wire artists seek to increase their rotational inertia and lower their center of gravity.
First, rotational inertia: If you're walking on a tightrope hundreds of feet above the ground, the very last thing you want to do is start rotating around it. The way to prevent that is to increase your rotational inertia.
Just as more force is needed to accelerate a more massive object from rest, more rotational force – or torque, as physicists like to say – is needed to spin an object with more rotational inertia. You can increase this by carrying more mass, and by keeping as much of that mass as far away as possible from your tightrope. Your tightrope is the one thing that you definitely don't want to become an axis of rotation.