okay...so I posted late at night and forgot about my units...it has been 25 years since i was in physics in college. Still think that a corked bat might cause negligible results though. I do agree that more control of the bat would create better contact but again...hard to measure.
As to Williams...he used a 33 ounce bat...about 2 ounces less than average of the time. Many people close to Williams and Williams himself often spoke about the swing and the eye as the key to their power. Williams generated torque and his eye was amazing. Watch Ruth, Williams, Ott, Gehrig, Mize, Mantle, and other hr hitters from that era. They often swung using whole body rotation generating bat speed, and torque.
Now watch Bonds, AROD, Ortiz, McGwire, Sosa, Fielder, Howard...they generate power mostly with upper body strength and even swing with just their hands. I am always amazed watching them hit homeruns at times. Griffey Jr was an exception in my mind and his power was generated with his smooth full body swing.
Also, lengths of bats matter as well...the lever affect does happen. It is easier to move a baseball with a longer bat than a shorter one. Anyone who hit a ball on the handle as opposed to the barrell can tell you this.
Type of wood is also important. How much the wood will indent and spring back before it reaches a breaking point is also a factor.
This is not to even talk about the ball and the elasticity of the ball, hitting it on the laces vs. the sweet spot, frictional, rotational mechanics of the ball, etc.
Physics has shown that swinging a heavier bat slightly faster is better than swinging a lighter bat much faster. There are some great articles on this...one found here.
http://www.acs.psu.edu/drussell/bats/batw8.html
Oh, btw, I did play baseball for ten years all the way through high school. I did have some experience with this. And just for honesty's sake... I used a 33 inch bat that weighed 33 ounces. I was not a power hitter at all...in fact, I barely hit period. I was used mostly as a fourth outfielder who could bunt, make contact with the ball, and walk.
Joshua