DeKALB | What’s the solution of 18 x 35? The human mind is a number crunching machine — even if you’re not in the middle of solving a math problem.

Don’t believe it? Just examine a quarterback.

When going for a pass, the quarterback has to grab the snap, drop back, evaluate the situation, find a receiver and then finally throw the ball.

And just chucking the ball isn’t enough. The quarterback has to decide on the trajectory, speed and angle of his pass.

He does all of these calculations and computations in just a few seconds.

Have you solved the multiplication problem yet?

While many factors determine if a pass is good or bad, one key is vital to all the rest: the spiral of the football.

Making a football fly in a spiral through the air and into a receiver’s hands as he crosses the goal line is not only aesthetically pleasing, but physically superior to any other form of passing.

But before we explain the physics of a spiral, we need to go through physics 101 and learn some terms.

Learning alert

A force is something that influences the motion of an object — like pushing or pulling.

In our scenario, we need to know about three forces: gravity, drag and torque.

Gravity is an attractive force created by very large objects.

In our case, Earth dominates gravitational pulls by causing everything to “fall” toward the planet at a rate of roughly 9.8 meters per second squared.

This force causes things thrown up and forward, like a football, to fall in the path of an arch. This is known as projectile motion.

Air resistance and drag are forces that are created by air molecules hitting an object flying through the atmosphere.

These forces hinder an object in projectile motion.

Finally, there’s torque, which is a force that causes rotation.

That’s enough class for today.

Now, how and why a spiral: First, let’s hear from the guys who throw hundreds of spirals a day.

“You have to stay on top of [the ball] coming down while snapping your arm,” said senior Phil Horvath, NIU’s starting quarterback against Ohio State Saturday. “I don’t know physics-wise how to put it in those terms.”

In other words, when Horvath is snapping his arm he is applying torque to the football. This torque causes the football to rotate.

The more torque, the faster the rotation. This rotation is what spectators see as the spiral.

But snapping your arm isn’t enough to make the ball get that tight rotation needed for deadly accuracy between defensive backs.

“What you try to do is put a lot of pressure on [the ball], and kind of spin it off your fingers,” sophomore NIU quarterback Dan Nicholson said. “You spin it out kind of like a screw ball. You want to kind of flick your wrist.”

With the additional torque from the wrist and fingers, the ball gains even more rotations per second — a tighter spiral.

When thrown, the football is bombarded by thousands of air particles. This creates forces, namely air resistance and drag, that try to stop the ball or ruin the accuracy of the pass.

The rotation of the ball reduces these forces by limiting the surface area that is being battered with air particles, while also stabilizing the ball as it is thrown so it remains accurate.

That’s it, presto.

In just those few seconds the quarterback uses his mind to calculate the torque needed to overcome air resistance as the ball flies in projectile motion, and boom, touchdown.