Recent content by Orodruin

  1. Orodruin

    What force causes precession?

    Yes, but not that they are parallel, which was the original statement.
  2. Orodruin

    What force causes precession?

    Yes, but ##\vec L = \vec r \times \vec p## does not imply that angular momentum is parallel to angular velocity so the latter cannot be a consequence of the former.
  3. Orodruin

    What force causes precession?

    Except it is not true. The angular momentum vector is not always in the same direction as the angular velocity vector. This is the case if and only if they are aligned with one of the principal directions of the moment of inertia.
  4. Orodruin

    Undergrad Curl of velocity vector in rotational motion

    No. It is a function of time as it changes with time, but it does not depend on spatial coordinates. If it did the object would necessarily change shape.
  5. Orodruin

    Undergrad Black hole questions

    That’s not starting from the singularity though 😉
  6. Orodruin

    Undergrad How does this configuration not create E field inside the conductor?

    It is exactly what they should look like.
  7. Orodruin

    Undergrad Curl of velocity vector in rotational motion

    By definition, ##\vec \omega## is constant is space - or you don’t have rotational motion. The curl does not contain derivatives wrt time so clearly letting ##\vec \omega## have a time dependence does not affect the result here.
  8. Orodruin

    Undergrad How can you model charge?

    The previous reply is excellent, so I will just add that the role of physics as an empirical science is to describe how things work, not to provide some underlying truth. You can always search for more detailed models, but physics will never describe what
  9. Orodruin

    How is x-vt a rightward moving wave?

    I’ll try to offer yet another perspective. The function ##f## describes the shape of the wave. We can consider a point on the wave with a particular constant value of ##f##, call it ##f_0##. Now consider how the point (or more generally, points) with this value are moving with time. We have...
  10. Orodruin

    Vector calculus: line element dr in cylindrical coordinates

    Because it was never there to start with. The position vector in cylinder coordinates is ##\vec r = \rho \hat \rho + z \hat k##, there is no ##\phi \hat \phi## term.
  11. Orodruin

    Praise 2025 PF Member Awards Ceremony

    Thank you everyone who voted for me and others! Not sure I deserved it this year considering how inactive I have been over the last 12 months, but still grateful. Almost instant mentorship and subsequent disqualification from member award polls? 😂
  12. Orodruin

    Undergrad Is this another "paradox" or a veritasium mistake?

    Yes, they would, but this would be attributed to the spaceship accelerating rather than the light following a curved path.
  13. Orodruin

    Undergrad What happens when two Neutrinos collide?

    If neutrinos collide they would undergo a regular weak interaction. This can either be elastic or inelastic depending on energy. An elastic scatter would not be very noticable. The cross section of interaction would increase manifold if the com energy approaches the weak scale.
  14. Orodruin

    Undergrad Where did the early photons go?

    … shortly put: if it is infinite today, it was infinite then. But with a smaller scale factor.