Calculating New Period of a Collapsed Sun Using Conservation of Angular Momentum

  • Thread starter Thread starter cheez
  • Start date Start date
  • Tags Tags
    Rotation
AI Thread Summary
The discussion revolves around calculating the new period of a sun that collapses into a dwarf star using conservation of angular momentum. The initial parameters include a radius of 8.1 x 10^8 m and a period of 38 days. Participants confirm that the angular velocity is calculated as 2π/38 days and affirm the relevance of conservation of angular momentum to the problem. Ultimately, the user expresses gratitude after understanding how to solve the problem. The conversation highlights the importance of angular momentum in astrophysical transformations.
cheez
Messages
26
Reaction score
0
Suppose a sun has a radius of 8.1 x10^8 m and a period of 38 days. If is collapses to a dwarf of radius 8.3 x 10^6 m, what is the new period (in days)? I= 2/5mr^2
I totally don't know how to do the problem. :frown:
Is it related to conservation of angular momentum?
Does the angular velocity equal to 2pi/38 days?
thx!
 
Physics news on Phys.org
Yes - to both questions! :)
 
Tide said:
Yes - to both questions! :)
thx, I get the answer now :)
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Angular Momentum- Conserved or not?
Replies
17
Views
413
Angular Momentum Problem: Mouse walking on a rotating turntable
Replies
5
Views
1K
Kepler's Third Law vs Conservation of angular momentum
Replies
8
Views
2K
How Does Angular Momentum Conservation Affect Asteroid Collision Dynamics?
7
Replies
335
Views
14K
Conservation of Angular Momentum sun problem
Replies
1
Views
6K
Conservation of angular momentum under central forces
Replies
4
Views
2K
Angular momentum conservation on a merry-go-round
Replies
5
Views
2K
Can Conservation of angular momentum be used?
Replies
6
Views
1K
Maximum duration of Solar eclipses
Replies
10
Views
2K
Find velocities when a mass leaves a system of a rod with two masses
Replies
10
Views
2K

Hot Threads

Recent Insights

Back
Top