Procedure MassRot in this worksheet animates the motion of two beads sliding without friction on a closed wire loop.

My question is stated in comments in the procedure where the beads' Angular Momentum vectors are calculated.

Beads_sliding.mw

The uploaded worksheet contains a second order ode with initial conditions which elicits an error message.
How can this error be avoided?

Bobs_sliding.mw

The two uploads are my attempt to solve Problem 177 in the book "200 More Puzzling Physics Problems" by authors Peter Gnadig, Gyula Honyek and Mate Vigh.

The first upload of a conducting rod moving with initial velocity along two arms of a triangle in a perpendicular constant magnitic field successfully produces an animation.

The second upload of the rod moving on the arms of a parabola produces a puzzling error message when executing the ODE

What actual error in the ODE results in this error message?

What changes to the worksheet will result in successful execution of the ODE and a successful animation?

Rod_triangle.mw

Rod_parabola.mw

I cannot find a description of the use of the form of dsolve and the following evaluation of its constants which are found in the downloaded worksheet.

Gnadig_2_problem_177_Rod_moving_on_a_wire_in_B_field.mw

The uploaded worksheet references two youtube videos.

The first one displays the animation of a simple device rotating about an axis tilted at a small angle from the device's principal axis having an intermediate moment of inertia.

The animation and accompanying verbal description demonstrate the Dzhanibekov effect.
The second video contains the first video's narrator's equations which produce the values used in creating the animation.

The uploaded worksheet contains my failed attempt to reproduce these values.

Please suggest the Maple 2020 compatible statements which correctly produce these values.

Dzhanibekov_effect.mw