BrainDen.com - Brain Teasers
• 0

# Perpetual Motion?

## Question

You have an area 100 yards in length by 10 yards in width

You have a solid steel orb (perfectly smooth) which weighs 100 pounds and has a circumference of 1 foot

You are on earth so you have normal gravity – there is no wind – and your surface is made of concrete

There are 3 hills within the 100 yards – each hill becomes smaller then the previous hill

You start the orb at the 0 yard mark

1.) What would the minimum height be at the initial starting point for the orb to make it to the end of the 100 yards?

2.) How high would the three hills be given the fact that the orb reaches each hills apex with little momentum to spare?

NOTE: please be kind – this is my first attempt at posting…

## 2 answers to this question

• 0

Baby Mac, I first want to apologize... While I was writing a new puzzle post, you posted your first puzzle (we were just a few minutes apart). I apologize because my puzzle will probably supersede your puzzle on the Google gadget only minutes after yours shows up. I know that if I were you, I would want my puzzle to remain visible for some time and NOT be replaced by someone else's puzzle. Had I known you were posting, I would have waited a day. So sorry.

• Is the area flat, other than the three hills?
• Does the orb have a starting velocity, or does it actually begin at the apex of the first hill?
• Are these hills actually round when viewed topographically? Or is your intent that these are rises and valleys which run transverse to the path of the orb, like speed-bumps?

I'm hoping these questions will help you to clarify your puzzle.

##### Share on other sites
• 0

I don't think that there is one answer to this problem.

I'm sure I could do this with a starting point of less than a foot, assuming that there is no friction.

## Create an account or sign in to comment

You need to be a member in order to leave a comment

## Create an account

Sign up for a new account in our community. It's easy!

Register a new account