OT: Cato June on NPR Squeezing Footballs

Yes, I have an advanced degree in that field. I guess I'm just assuming that less mass and more absorbtion of force and more friction would lead to less momentum. Anyhow, he did underthrow his receivers several times. 

Let's go over this again, Joegeo.  It's not as easy as you might be imagining.

I had a post a few weeks ago, about which would fall fastest to the ground if jumping out of an aircraft (without parachute) -- an elephant or Fred Jackson?  We're taught, everything falls at the same speed.  Not quite right, in an atmosphere.  The downward acceleration due to gravity is the same -- in a vacuum.  But air resistance -- DRAG -- pushes against (upwards) on the object.  The force of drag is a combination of its shape/surface and its mass.  If two objects have identical shape and surface but different weights, then the force of drag is the same, and the lighter one declerates faster.  Like, if you had a normal baseball and also a baseball filled with aerogel (super-light-weight interior, but identical exterior), and dropped both from a very high height, the heavier ball will hit first -- the lighter one will "float down" a bit.  More technically, the heavier ball has a higher "terminal velocity" (where the force of drag UP is equal to the pull of gravity DOWN).

So, on a football, there are similar considerations -- the initial force of the throw, offset by the force of drag.  Actually, I did a senior class Aero project on footballs, in the wind tunnel in the old UM AERO building on North Campus, measuring forces on them.  (We took a Nerf football and stuck a servomotor up it from the backside, to create the spin, and attached the motor to a brace in the wind tunnel, and measured the forces of the air moving over the ball, then plugged the results into a PC running a BASIC software program we wrote to calculate the effect.  That's 1986 for ya.)  We learned the physics of the ball from watching the QB in practice before a game -- and, huh, who was that, in 1986?  Yes, it was...JIM HARBAUGH.  Not kidding.  So, I bring you, the physics of a football, HARBAUGH'd.  (What we noticed is, the angle of attack, or the 'attitude' of the ball -- its orientation with respect to the direction it was pointed -- seems constant during its flight; it rotated about at the same rate the path of its flight bent, keeping a constant AOA.)

So what are the factors?

1.  The speed at which it leaves Tom's hand might be slightly different.  He might grip a deflated football a little better, and better grip implies slightly more force on the ball.  (Although grip could relate more to accuracy.)  Also, the lighter ball is going to be slightly faster, because obv, pushing a lighter objecf gives you more acceleration than a heavier one.  But the net weight difference is like a tiny fraction of an ounce.

2.  The deflated balls potentially might have a slightly different drag coefficient than an inflated one, because the shapes might not be exactly identical.  There is also an issue of whether the air's push against the ball, in flight, slightly changes the shape of the ball -- a deflated ball might have its "nose" pushed back a bit more, flattening it, tending to make it less aerodynamic and hence more draggy.  So a deflated ball might have a slightly higher drag coefficient.  But, this effect is probably de minimis or nonexistent at slow speeds.

3.  Because the deflated ball is ever so slightly lighter, if it has basically the same or slightly more drag, it might slow down FASTER than the inflated ball.  (More force pushing against it, on a lighter object, equals more decelleration.)

4.  One more thing.  A football sort of generates "lift" in flight, due to its spinning around its long axis -- like a curveball.  The seams and laces, as the ball spins, creates movement of the air around it, tending to lift it.  Again, if an inflated and deflated ball end up having identical shape, the lift is like the drag -- the same.  But a slightly deflated ball, like mentioned in #2, might flatten out a tiny bit more, which I'd think would tend to decrease the lift.  More lift = more time in flight, making it go farther.  So the inflated ball might have a tiny advantage in terms of flight time.  (OTOH, better grip on the ball might mean, slightly MORE spinning, which might INCREASE the lift.)

So, does #1 offset the effects of #2/#3?  And what is the net effect of $4?

My guess is, the deflated ball will TEND to fly a LITTLE SHORTER than an inflated ball, given the physics of the drag and lift.  If Tom's grip is better on the deflated ball, he might get better accuracy which is the tradeoff.  But possibly, his better grip might let him put more speed or spin on it, in which case, #1 and #4 predominate (it leaves his hand with slightly more speed, and generates slightly more lift) and it goes slightly farther.

So, uh, airchair physics tells us, "softer ball MIGHT NOT travel as far or fast." 

Sorry you asked?  You've been HARBAUGH'd.