wrobel's latest activity

Only two solutions: the point moves strictly vertically up and down, or it traces a parabola.

Thought some teachers might find this useful. A wheel of radius ##R## rotates in a vertical plane about its fixed center. A speck of...

see https://arxiv.org/abs/2607.24825 for details

The mechanism ABCD by itself has 2 degrees of freedom

Perhaps it would be clearer to write: $$\sin x=a,\quad |a|\le 1\Longrightarrow$$ $$x=\arcsin a+2\pi n$$ and $$x=\pi-\arcsin a+2\pi...

"Not making physical sense" and "not making geometrical sense" are in fact two sides of the same coin

Angular acceleration is a vector defined for a rigid body, not a system of rigid bodies. As a whole, it's a great problem — practically...

I feel that if we want to generalize the equations of a continuous medium's motion to an arbitrary Riemannian manifold, then the only...

On a curved manifold, velocities at different points belong to different tangent spaces, so they cannot be added directly. You need a...

I am not aware of a way to in general fix this integral in the sense that there is a unique 1:1 correspondence between this integral and...

For high school, such a problem-solving strategy is OK, but at the university level, it is too weak. For example, this is a mistake...

Consider the flow of a continuous medium with a smooth velocity field ##\boldsymbol v(x)## in ##\mathbb{R}^3\ni x##. The density of the...

It means I do research without affiliation to any university or research institute. I still respect mainstream physics and try to...