# I Determine the size of a planet

1. Sep 2, 2016

### Amber_smith

Given a planet that rotates at 5000mph And the length of a day being 52 hours how big would this planet be?

2. Sep 2, 2016

### Borg

Last edited by a moderator: May 8, 2017
3. Sep 2, 2016

### Amber_smith

I'm sorry i didn't know. this isn't for homework or anything. It was just a general question. If someone could point me in the right direction of the formula to figure it out myself that would be as helpful

4. Sep 2, 2016

### Borg

From the question, you are basically trying to determine the circumference of a planet. So, if a person is standing on the surface, how far would they travel in 52 hours? (I.E. the length of time for them to rotate once).

5. Sep 2, 2016

### Drakkith

Staff Emeritus
I don't have time to provide an in-depth answer, but here's the wiki page for circular motion. The first couple of equations in the formula section should be exactly what you need to figure this out. (at least I think so. I only had a minute or two to look into this)

6. Sep 6, 2016

### |Glitch|

Your question contains the answer: 5,000 miles per hour for 52 hours = 260,000 miles. Therefore, the circumference of your planet must be 260,000 miles. That would make your planet ~10.45 times larger than Earth, or 82,761 miles in diameter.