Post: 500k vBux Challenge
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01-19-2011, 01:50 AM
#1
elfmotat
Rᵤᵥ - ½gᵤᵥR ∝ Tᵤᵥ
The Problem
Originally posted by another user
There exists a spherical planet about the size of the Earth with a uniform density of 5000 kg/m³. A hole (negligible mass removed) is drilled through the diameter of the planet so that objects can be dropped and freely fall. A bowling ball is lowered into the hole to a height of 1,000,000 m above the center of the planet where it is released from rest. How far away is the ball from where it was released after 3 hours? (Assume the planet is completely at rest.)
01-19-2011, 03:33 AM
#11
+tA. Rick
Former Staff
Originally posted by koolkarpet
This question is hard. There's no mass or radius given.
Unless I'm wrong, those values need to be interpreted by the uniform density given. But then you'd need to figure out what uniform density is beforehand.
Make connections. :y: I haven't learned this subject yet, but it's a good way to make progress.
01-19-2011, 03:42 AM
#12
the stuff
League Champion
Originally posted by tA.
Unless I'm wrong, those values need to be interpreted by the uniform density given. But then you'd need to figure out what uniform density is beforehand.
Make connections. :y: I haven't learned this subject yet, but it's a good way to make progress.
Make connections. :y: I haven't learned this subject yet, but it's a good way to make progress.
01-19-2011, 04:09 AM
#14
elfmotat
Rᵤᵥ - ½gᵤᵥR ∝ Tᵤᵥ
Originally posted by koolkarpet
Yeah I know, it's related to Gravitational acceleration. I have the universal gravitational constant. It's just a matter of finding the other values. I think you'll need the density of the surface of the planet along with the radius to find the mass. With the mass, you can find g. Then from there I don't know what to do.
You're on the right track. What would the acceleration due to gravity be? Would the fact that you're inside the planet make a difference to the normal g=-GM/r² ? :biggrin:
---------- Post added at 10:59 PM ---------- Previous post was at 10:56 PM ----------
Originally posted by All
your not allowed to give away vbux
What? You high, son?
---------- Post added at 11:09 PM ---------- Previous post was at 10:59 PM ----------
Since I basically already gave the first part of the problem away, I'll tell you guys. The trick is Gauss's Law:
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01-19-2011, 05:35 AM
#18
italianboss
☆Level 1 Trustworthy☆
Originally posted by elfmotat
I will be giving 500,000 vBux to the first person to answer correctly.
The Problem
Rules / Guidelines
- All work must be shown using LaTeX or something similar: You must login or register to view this content.
- Approximate the answer to the nearest meter
- You have one week from today (I will post the answer next Tuesday)
- I may give hints along the way
The Problem
Rules / Guidelines
- All work must be shown using LaTeX or something similar: You must login or register to view this content.
- Approximate the answer to the nearest meter
- You have one week from today (I will post the answer next Tuesday)
- I may give hints along the way
i finished it and i think i got it i sent it to you in ur pms
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