- #1
tolove
- 164
- 1
In short:
Why are galaxies flat?
In more detail:
A very large mass M is at rest in vacuum, rotating at point O. Its axis of rotation is the xz-plane with angular momentum [itex]\vec{L}[/itex] directed along the positive y-axis. What forces do the following masses experience?
(Units of distance are arbitrary and only given for orientation. Please explain if the actual distance in a given orientation is important.)
1) m1 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex].
2) m2 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{j}[/itex].
3) m3 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex] + [itex]\hat{j}[/itex]
4) m4 is set into circular orbit in the xz-plane, initial position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex].
5) m5 is set into circular orbit in the yz-plane, initial position [itex]\vec{r}[/itex] = [itex]\hat{j}[/itex].
6) m6 is set into circular orbit, at angle ∅ = 45° with the x-axis, initial position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex] + [itex]\hat{j}[/itex].
Further, a large mass M undergoes rotation. This implies that particles in M are moving with angular velocity w = rv. However, in the case of black holes, what is the radius r? If black holes are not considered a point, then what keeps them from becoming a point?
Thank you very much for any help in understanding these confusing things!
Why are galaxies flat?
In more detail:
A very large mass M is at rest in vacuum, rotating at point O. Its axis of rotation is the xz-plane with angular momentum [itex]\vec{L}[/itex] directed along the positive y-axis. What forces do the following masses experience?
(Units of distance are arbitrary and only given for orientation. Please explain if the actual distance in a given orientation is important.)
1) m1 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex].
2) m2 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{j}[/itex].
3) m3 is placed at rest with position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex] + [itex]\hat{j}[/itex]
4) m4 is set into circular orbit in the xz-plane, initial position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex].
5) m5 is set into circular orbit in the yz-plane, initial position [itex]\vec{r}[/itex] = [itex]\hat{j}[/itex].
6) m6 is set into circular orbit, at angle ∅ = 45° with the x-axis, initial position [itex]\vec{r}[/itex] = [itex]\hat{i}[/itex] + [itex]\hat{j}[/itex].
Further, a large mass M undergoes rotation. This implies that particles in M are moving with angular velocity w = rv. However, in the case of black holes, what is the radius r? If black holes are not considered a point, then what keeps them from becoming a point?
Thank you very much for any help in understanding these confusing things!