How Massive Must a Neutron Star Be to Keep Its Surface Intact While Rotating?

wood_magpies
Messages
1
Reaction score
0
certain neutron stars rotate at about 1.0 revolutions per second. If such a star has a raduis of 20km, what minimum mass must it have so that material on its surface doesn't fly off during the rapid rotation?


ive tried working out the centripetal acceleration, being 7.89 X10^8
then subbed into the equation, assuming that m=1:
ive made m=the material on the surface and given it a value of 1
M= mass of neutron star
G= gravity constant = 6.674 x 10^-11

F = GMm/r^2


the answer i got turned out to be 4.7322 x10^24kg
but a few of my friends got 2.236x10^24 kg

can anyone help please?
 
Physics news on Phys.org
With the given values, I get same result as you. You do seem to have a type in the magnitude of the centripetal acceleration, though.
 

Thread 'Initial conditions for orbits around a wormhole'

Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
View full post »

Thread 'Help to convert units of a simple formula'

The value of H equals ## 10^{3}## in natural units, According to : https://en.wikipedia.org/wiki/Natural_units, ## t \sim 10^{-21} sec = 10^{21} Hz ##, and since ## \text{GeV} \sim 10^{24} \text{Hz } ##, ## GeV \sim 10^{24} \times 10^{-21} = 10^3 ## in natural units. So is this conversion correct? Also in the above formula, can I convert H to that natural units , since it’s a constant, while keeping k in Hz ?
View full post »

Similar threads

I Energy Released From Dropping Things Onto Neutron Stars
Replies
20
Views
2K
What is the Minimum Mass for a Rotating Neutron Star?
Replies
6
Views
2K
B Acceleration of a proton/electron toward a neutron star
Replies
6
Views
2K
Understanding Neutron Star Rotation: Calculating Kinetic Energy
Replies
1
Views
2K
Centripetal acceleration of Neutron stars
Replies
1
Views
6K
Universal Gravitation and neutron stars
Replies
2
Views
9K
Centripetal Acceleration of pulsar
Replies
1
Views
2K
How fast does the Earth need to move to provide centripital acceleration
Replies
43
Views
8K
Total centripetal acceleration ringworld
Replies
1
Views
8K
How Fast Must You Throw a Baseball to Orbit an Asteroid?
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top