Wednesday

September 17, 2014

September 17, 2014

Posted by **Mark** on Wednesday, March 4, 2009 at 4:23am.

Spinning too fast

The rate of rotation of astrophysical objects that are held together by gravity (e.g., stars or planets) cannot be larger than a certain maximum. Rotating faster than this rate will tear the star apart. Let’s find the expression for this maximum rotation rate.

a) You are sitting on the equator of a star of radius R that is spinning about its axis with period P. What is the rotation speed that you have on the equator?

b) Using your expression for the rotation speed, what is the centrifugal acceleration that you experience on the equator?

c) The star has mass M. What is the gravitational acceleration that you feel on the surface?

d) Now equate the centrifugal and gravitational acceleration, and find the period of rotation when they are equal. What happens if the star rotates faster than this period?

e) Calculate the limiting rotation periods for the Earth and for the Sun. Write them in the most appropriate units (e.g., seconds, minutes, hours, days, years, etc.). Find the ratio of the critical rotation period for the Earth to the current rotation period. The Sun is rotating with a period of 25 days. Find this ratio for the Sun as well.

- Another astronomy (algebra-based physics) question -
**drwls**, Wednesday, March 4, 2009 at 9:19amEnough, already. Show your work for further help

**Answer this Question**

**Related Questions**

Chemistry - Small gene Big Plasmid Question 2 Part E is wrong. Question 2 Part F...

math - I forgot how to solve this grade 11 review package question 5) A graph ...

Astronomy/Physics - I'd love thorough solutions to these problems, but simply ...

algebra 2 - i need help with my algebra 2 homework, the section is called using ...

Physics Drwls - I was wanting help with my physics post and since no one replied...

Deciding on a H.S. Science Course - I'm currently a sophomore, and I need to ...

Math - Is there a case when you might prefer algebraically over graphically ...

biology - Small gene big plasmid Question 2 Part E wrong. Question 2 Part F ...

Child development - Using these steps, consider a cognitive “problem” a young ...

math - how do you know when an equation has infinate many solutions and how do ...