College Physics Question Need Help Please? ASAP!?

Question

I need help in solving a Physics puzzle question and help is highly appreciated.

The question is:

Imagine, for the purpose of this excercise that the earth is a smooth sphere. A rope is tied tightly around the earth at the equator. If the rope is then loosened so that 9 FEET of slack is now added uniformly around, which of the following creatures could possible crawl under the rope?

A) Amoeba
B) Ant
C) Mouse
D) Cat
E) Large Dog
F) Donkey
G) Giraffe

Thanks!

well im in my first day of class and my professor is giving us these problems.

can you elaborate on how to plug the numbers in? So i plug the 9 in the L or leave the L alone? the earths is 25000 miles correct?

Answer 1

The rope is 2*Pi*r and you add x to this and get a new radius that is R. Then 2*Pi*R = 2*PI*r+x and then R = r+ x/(2*Pi) so the extra height is x/(2*Pi).

I have no idea what kind of measure "feet" is, how about meter?

Answer 2

This is NOT really a college-evel physics question at all.
Let the original rope length to be L feet and earth radias at equator to be r feet, we have: 2*pi*r = L
Now, we have a rope length L+9 (feet), obviously the new radias would be about 1.4 feet longer than r, since:
2*pi*(r + 1.4) = L + 9.
Therefore the answer should be E) Large Dog.