Recent content by SpaceThoughts

About Me I am a danish musician with love for classical physics. My knowledge of physics is quite elementary and at the high school level. My thoughts have for decades played with classical physics when there has been time to reflect, and the theme has always been a curious and thorough analysis...

When winding a bike wheel up in an elastic double string in the ceiling, and then let the wheel spin vertically, it unwinds more slowly than if it was not spinning. I tried it. But it if a spinning disk is placed in a solid construction like this (photo attached) , and can only rotate...

Let me ask the same question in a less confusing way: I lift the front wheel of my bike off the ground and make it spin. I turn the handlebars right-left-right-left. I feel the resistance of moving the handlebar back and forth. The faster the wheel spins the more resistance. Will turning the...

Imagine a spinning wheel built into a hand size vacuum box. There is no friction between the axe bearings of the wheel and the box. Let's say that the wheel rotates with 60 RPM. Am I right if I assume: 1. The wheel continues to rotate, approximately as if in space. 2. It is not possible to...

A known force is doubling (egal) over a known distance, accelerating a mass. How do I calculate the final velocity of the mass at the end of the known distance , when the mass has doubled? I don't know the time. The mass is accelerated from 0 meter and from 0 velocity.

This is a really fine answer. Thanks a lot, it moves me forward ...

I am looking for a rotation devise like that one in this video below (from 00:40 seconds). Does anyone know where to get one, or have any idea about how to create a nice and stable rotation setup for experiments without too much hassle and DIY? A bike wheel won't do, a disk is better, because I...

When for example someone is demonstrating the conservation of angular momentum, switching between two different rotations. If I only know the data of the one rotation scenario, and decide a distance to move the masses along radius, will I then be able to calculate the new resulting rotation...

Hi there ... How do I calculate the change of angular velocity, when demonstrating conservation of angular momentum? I mean the change of angular velocity depends on the ratio between the two (rotating) masses that moves a distance along radius, and the (rotating) mass of the system itself. In...

In what way? The setup is quite simple ...

Nice expression, and thanks for spending your time on me:-) Yes, I should say work done by the hands in both cases. Force is used in both flipping the wheel upside down and back. If we started the experiment with the wheel upside down, it would be the same cycle, only the direction of the...

That is what I am asking here. There seems to be no heat loss. Comparing the start scenario with the end scenario shows a difference.

Thanks for both answers. I’ve been thinking a lot about the experiment done in the video above, and to me it seems we are losing energy every time we recycle the experiment, questioning conservation of energy. Think of the laboratorium as an empty isolated system only containing what we need...

Hi. I searched and found no answer to this simple question: Is the spinning wheel in this videoclip keeping the same rotation (kinetic energy) when flipped upside down and back again? (if we forget about friction)

Thanks for your kind and clear answer. I fully understand now, and yes I am aware of radius of the balls etc.