I have three questions that I could not find in my book, even though they are probably there. Plz help, I have to do well on this quiz, or I'm dead!!!

1) What two forces are at work in a nebula that is not creating a star?

2)What happens to the rocks in the center of a planetesimal after the planetesimal reaches a diameter of 350 km?

3)Eventually, a planetesimal heats up so much that not all of the heat energy can escape from the inside the planetesimal. What happens to the rocks in the center of a planetesimal then?

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Ok, I think the answer to #3 was that they melt. Is that right? Plz help me, like I said, I have a really big quiz tomorrow that my science teacher just told about TODAY and she gave us the twenty-question study guide TODAY. Thank you so so so so so so so much!!! You guys are a GREAT help with my assignments!!!

1) To vague to answer. Forces in nature are gravity, nuclear and electromagnetic. I don't know what the question means.

See:

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2)Melt I would think. Depends on surface bombardments and age of planetesimal.

3) They would become plastic like at first. If the planetesimal continued to grow, yes, they would melt.

http://www.google.com/search?hl=en&lr=&as_qdr=all&q=planetesimal+diameter+core+molten+bombardments+&btnG=Search

Thank you very much, I found out the day of the quiz that we didn't need to have the first question answered. Thank you for helping me out!

You're welcome! I'm glad I could help. Good luck on your quiz, and remember to study and review the information thoroughly. If you have any more questions, feel free to ask.