Photo: Yi Chen (Flickr)
Try balancing a baseball bat straight up and down on the palm of your hand. When you let go with the other hand, the bat starts to fall. But if you’re quick, you can move your hand in the same direction to keep it upright for a little longer.
Baseball Bat Physics
With some experimenting, you’ll find that the bat stays up longer if you put the heavy end up. That’s because in that position it falls a little more slowly, which gives you more time to respond before it falls off your hand.
But why does it fall more slowly with the heavy end up? After all, if you drop a light ball and heavy ball, they should fall at about the same speed.
The difference is that as the bat starts to fall, the bottom of the bat stays still on your hand while the top of the bat moves in an arc, both down and to the side.
A Little Bit Of Gravity
So gravity has to pull the bat down and get it moving horizontally at the same time. Even though a light object and a heavy object will fall at the same speed, it takes longer to get the heavy object moving horizontally. That’s why pushing a VW is easier than pushing a Cadillac.
So a bat that’s heaviest at the top, where most of the horizontal movement takes place will take longer to start moving than a bat that’s heaviest at the bottom. And that gives you more time to catch the bat before it falls.
Next time you’re at the circus, watch the balancing acts. You’ll see that whenever possible the objects they’re balancing will be weighted at the top.