Puzzler

Here's a brain teaser for you:

I'm finishing up an article on the All-American Soap Box Derby. The Derby is for engine-less carts; the only thing accelerating the racers down the hill is gravity. One boy tried to cheat by holding a bowling ball between his legs and letting it go at the top of the hill so it would roll forward and hit the nose. The theory is that this would give his cart a little extra boost.

Here's the question: Would the cart go any faster? If so, why and under what circumstances?

I've already called my Physics major brother and figured it out--I'm just wondering how smart my f-list is. *evil grin*