What's all this I hear about Inertia ?

[John Delacour]

At 14:47 -0400 29/9/08, David B. Stang wrote:

>If a perfectly rigid key weighed 1000 pounds overall but were
>balanced to have a certain down-weight, it would behave and feel
>the same as any other rigid key with the same down-weight

 From a tall ceiling hang two balls 6" in diameter, one made of 
expanded polystyrene and the other of lead.  Apply gentle pressure 
horizontally to the lead ball and you will find you can move it an 
inch with practically no effort.

Now take your shoes off and kick it hard.  See if there is any 
difference when you do the same with the polystyrene ball.

JD