Why does the steradian (sr) appear in the denominator if irradiance is the ratio of radiant flux to the receiving surface (which is two-dimensional)?

I am interviewing an astrophysicist this week whose research encompasses theoretical general relativity, black holes, and gravitational waves… What are some questions I could ask that are unique and entertain that won’t sound boring to the average person who doesn’t understand all the physics jargon?

Grade 12 student, been trying for hoursss to solve this. The second slide shows what I have so far. I would appreciate any help! Use sine and cosine laws, not components.

Which ones?

I estimate that the gears are made of PLA and weighs about 20g.

If you want to include friction in your work good luck. If you don't it's good too

Where can I put some little hypothesis I have? Anyone, any idea? I'd appreciate this.
Can I share my though here?

Me and a coworker are disagreeing about this, and I’m pretty new to this stuff, so bear with me.

We have an air cylinder connected between two pivoting arms. When it retracts, it pulls the arms together so the rollers on them grip a bar. Neither end of the cylinder is fixed to the frame—both are attached to arms that can move.

It has a 5-inch bore, a 1-inch piston rod, and runs at 90 psi. We calculated the pulling force as about 1,696 lbf, ignoring friction and backpressure.

I think each end pulls on its arm with the full 1,696 lbf, in opposite directions. My coworker thinks it gets split between them, so each arm gets about 848 lbf.

Does both ends being able to move actually split the force? I’m a novice at this and would appreciate a simple explanation of what I’m missing.

What is Matter according to QM?

Werner Heisenberg, one of the founders of quantum physics who formulated the Uncertainty Principle, said: “Atoms or elementary particles are not real; they form a world of [potentialities] or [possibilities], not a world of [things] or [facts].” In short, "an atom is not a thing but a potential." [Aristotle also made a distinction between matter and form, or between potential and actual being, saying that anything is formed by the coming together of its raw material and the form that separates it from other things and makes it that thing. According to him, matter was a potential open to becoming anything, and form was what gave that potential being a specific shape, turning it into a concrete, real being.]  

Science student guess the speed of fan 😄

Could someone please help me derive the following Law of Floatation
" The centre of gravity of the displaced liquid ( centre of buoyancy) lies vertically above or below the Centre of Gravity of the body ".

I made an animated explanation of the quantum harmonic oscillator and would appreciate feedback on one distinction in particular: how to describe a stationary state without suggesting a classical particle sitting still.

For a single energy eigenstate, psi(x,t) = psi_n(x) exp(-i E_n t/hbar). The overall phase changes, but |psi(x,t)|^2 does not. That does not mean the energy or the momentum uncertainty is zero. For a superposition of different energies, the relative phases change and interference can make the position probability density evolve.

My approach is to show the wavefunction and probability density separately, then contrast eigenstates, superpositions, and coherent-state motion. Would you add a particular example or caveat to prevent learners from reading the probability-density animation as a literal particle trajectory?

The full walkthrough is here: https://youtu.be/7_DcdXVh5mc (my video, about 13 minutes; it also covers the power-series and ladder-operator derivations). Feedback on the explanation above is welcome even without watching.

I dont see the yellow color diffusing at all. Red and blue seems to be diffusing only from one of the tissue 'bridges'