Stresses in a rotating object?

  • Thread starter Thread starter billyboy
  • Start date Start date
  • Tags Tags
    Rotating
billyboy
Messages
2
Reaction score
0
Has anyone considered the following. If I have a really big disc and rotate it at a certain angular velocity. Then at some distance from the centre the tangential speed of the disc will equal the speed of light and any distance beyond will have a speed greater than that of light. Obviously this cannot be the case and some strange time dilation and length contraction effects will take place. Can anyone explain exactly what does happen? Presumably some stresses are set up in the disc which could be calculated?
 
Physics news on Phys.org

Thread 'Describing the Big Bang'

I started reading a National Geographic article related to the Big Bang. It starts these statements: Gazing up at the stars at night, it’s easy to imagine that space goes on forever. But cosmologists know that the universe actually has limits. First, their best models indicate that space and time had a beginning, a subatomic point called a singularity. This point of intense heat and density rapidly ballooned outward. My first reaction was that this is a layman's approximation to...
View full post »
Thread 'Dirac's integral for the energy-momentum of the gravitational field'

Thread 'Dirac's integral for the energy-momentum of the gravitational field'

See Dirac's brief treatment of the energy-momentum pseudo-tensor in the attached picture. Dirac is presumably integrating eq. (31.2) over the 4D "hypercylinder" defined by ##T_1 \le x^0 \le T_2## and ##\mathbf{|x|} \le R##, where ##R## is sufficiently large to include all the matter-energy fields in the system. Then \begin{align} 0 &= \int_V \left[ ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g}\, \right]_{,\nu} d^4 x = \int_{\partial V} ({t_\mu}^\nu + T_\mu^\nu)\sqrt{-g} \, dS_\nu \nonumber\\ &= \left(...
View full post »

Thread 'A sufficient condition for integrability of equation ##\nabla g=0##'

In Philippe G. Ciarlet's book 'An introduction to differential geometry', He gives the integrability conditions of the differential equations like this: $$ \partial_{i} F_{lj}=L^p_{ij} F_{lp},\,\,\,F_{ij}(x_0)=F^0_{ij}. $$ The integrability conditions for the existence of a global solution ##F_{lj}## is: $$ R^i_{jkl}\equiv\partial_k L^i_{jl}-\partial_l L^i_{jk}+L^h_{jl} L^i_{hk}-L^h_{jk} L^i_{hl}=0 $$ Then from the equation: $$\nabla_b e_a= \Gamma^c_{ab} e_c$$ Using cartesian basis ## e_I...
View full post »

Similar threads

I Non-Inertial Relativistic Dynamics
Replies
18
Views
1K
B Relative rate of clock ticks on the radius of a rotating disc
Replies
46
Views
4K
I Perceive Length Contraction VS Terrell Penrose
Replies
14
Views
2K
I Terrell rotation is confusing!
Replies
8
Views
2K
I Confusion about adding angular velocities
Replies
4
Views
2K
A 1-Way Speed of Light
Replies
42
Views
684
B Why does length contraction occur and how does it relate to time dilation?
2
Replies
63
Views
5K
I What causes time dilation and length contraction
Replies
10
Views
2K
Thin rotating disc under constant acceleration.
2
Replies
80
Views
14K
I Charge movement relative to magnetic field frame dependence/invariance
Replies
5
Views
891

Hot Threads

Recent Insights

Back
Top