PARNEVIK'S ROPE TRICK

[golfdonkey]

Does anyone remember the answer to the question that Jesper Parnevik was pondering and which he said was responsible for him missing a short putt at Loch Lomond?

"If you put a rope around the 25,000-mile circumference of the Earth and then placed another rope three feet higher, how much longer would the second rope be?"

I know the answer was surprising - can anybody help?

 

[Shooter_McGavin]

I've got a question:

WHO CARES?!the guy ate volcanic dust, you shouldn't listen to any thing he had to say!

 

[Severiano798488]

Very baffling....I had no idea the enigmatic Swede was a physics expert as well as the owner of the most extraordinary cap in golf

The old "spike mark" excuse seems a bit predictable by comparison

 

[peter_constant]

no wonder he missed the putt - I could barely take the club away if I was thinking of anything like that

bit like the classic one to putt your opponent off... do you breathe in or out on your backswing?

guaranteed to have them struggling with their swing for a hole or two

 

[muttleee]

A bit of O-level maths is called for:

Length of a rope around the world = 2*pi*r where r is the radius of the earth.

Length of rope 3 feet above the surface of the earth = 2*pi*(r+3) = 2*pi*r + 6*pi

The difference between the 2 is therefore (2*pi*r + 6*pi) - 2*pi*r = 6*pi

Since pi is about 3.14, this means that the rope 3 feet above the surface is about 18 feet 10 inches longer than the one on the surface. Nuttin to it.

 

[golfdonkey]

Excellent! Now I can bore all my friends, sorry friend, at the chess club.

 

[Trueblue]

Golfdonkey that is the most extraordinary thing i have ever read! What do you think about over the ball...nuclear fusion, Laura Davies in a bikini, Furyk's fluid swing?

 

[Shooter_McGavin]

Thats enough about laura davies for one day! And enough about Jim Furyks fluid for that matter!!

 

[Dave3498]

If the circumference of the earth is 25,000 miles (132,000,000 feet) then by dividing by Pi you will arrive at the diameter, which is 42,016,904.98 feet. If the second rope is 3 feet above the first, (6 feet on diameter) then the diameter of the second rope is 42,016,910.98 feet. Multiply the second figure by Pi and you will arrive at the length of the second rope, which is 132,000,018.8. So the answer is that the second rope is 18.8 feet longer. I reckon.

 

[muttleee]

You don't even need to do all those calculations because the radius of the earth cancels out so you don't have to know what it is:

2*pi*(r+3) - 2*pi*r = 6*pi = 18' 10" or so.

 

[Dave3498]

Your solution is a lot more sophisticated than mine Muttlee, but I'm not that clever, so I have to do it the long way. We both got the right answer though, which is the important thing.

 

[MacMachattie]

I've just finished reading this Open University style thread and frankly I'm amazed at how good all your maths is. Are you all that good when it comes to totting up a scorecard at the end of a round?

 

[muttleee]

The 2 solutions are basically the same...it's just you put the actual numbers in.

 

[furyk_or_unique]

I've spent some time reading all the comments here and quite frankly my brain hurts and I'm going to have to go and lie down in a quiet, cool room for a while.
I think it's all that talk of "Pi" which I'm sadly going to have to give up this year as part of a self-enforced weight loss campaign