I went through this interesting exercise in this teaching workshop this morning. I liked it so much, I wanted to invite you to play along at home. It's actually in two parts, so here's part I.
Suppose you have two tracks that look like this:
Track A: \o \ \_________________________________________________ Track B: \o \ \______ ______________ \ / \_________________________/
You release two balls from the top of the two tracks at the same moment and they roll along. The question is which ball will get to the end first. Your exercise is to: a) decide on your answer, b) write your reasoning in the comments, c) read other comments and possibly update the answer.
Your original answer:
Your answer after reading comments:
I changed my mind after reading the comments:
I expect some of you may have seen this exercise before; feel free to answer and leave your reasoning in the comments, but don't state that you've seen it before, otherwise people will trust your answers too much. :)