> The physics of struck golf balls appears to be terribly
> complex.
An exact description would be very complex indeed.
> I actually found "authoritative" sites that I'm certain were
> completely incorrect. For example, one site stated that the
> speed of a struck ball could never be greater than the speed
> of the clubhead.
The obvious limiting case is
ball speed = TWICE clubhead speed
as should be obvious in the center-of-mass frame, in the
limit of a heavy club and a light ball.
> If that were true, then shouldn't
> you be able to throw a golf club at least a good percentage
> of the distance you can hit the ball
Physics suggests the percentage is less than 50%.
> (a golf ball benefits
> from the dimples, which keep it aloft for a longer period of
> time).
"Keeping it aloft" is not a very scientific statement.
Dimples do promote turbulence which promotes boundary-
layer adhesion resulting in pressure recovery and hence
less net pressure drag. For this reason and many others,
the ball is more aerodynamic than the thrown club.
Presumably a major contribution to the energy budget
is internal friction due to deformation of the ball
during the ball/club collision.
...
> This seems to indicate that the ball struck in the
> atmosphere will actually fly farther, the reason being that
> it stays aloft for a similar period of time, but its launch
> angle is less than 45 degrees, so its horizontal velocity is
> greater.
>
> This doesn't "seem right" to me.
It's not right. Put in the numbers. What you call
a "similar" amount of time is similar but less. The
horizontal velocity is similar but greater. Changing
the angle (and nothing else) in the absence of aerodynamic
forces makes *no* change to first order. To second order,
the change is necessary deleterious. This is practically
the defining property of an optimum, and 45 degrees is
in fact optimal in the absence of aero forces, as you
can easily show.
If you allow aerodynamics, all bets are off. If you
can hit a ball 150 yards sideways you should be able
to hit it 100 yards straight up. Then imagine that
it sprouts wings and glides away. You can build
gliders with a 40:1 glide ratio. That gives you
4000 yards sideways in no-wind conditions.
Of course good gliders have a huge aspect ratio,
and a ball has about the smallest imaginable
aspect ratio, so you would be lucky to get a
1:1 glide ratio. This is enough to make it possible
that the ball in air could go farther than the
ball in vacuum, but not by much.