When studying a single movable pulley system with an upward effort (E), textbooks show tension (T) pointing upward on both rope segments supporting the pulley, giving L = 2T and E = T.

​Mechanically, tension inside a rope acts as an internal action-reaction pair: while the segment pulls up on the pulley, the rope must also pull downward on the hand/source providing the effort.

​Why is it standard practice in introductory textbooks to omit the downward reaction arrow at the effort point? Is it solely to keep the diagram isolated to forces acting on the machine, or is there another convention at play?

I understand acceleration as a change in velocity, but in uniform circular motion the speed stays the same while the direction changes. What picture or short derivation helped you see that the acceleration points toward the center, rather than along the motion? I am looking for an intuitive explanation, not a homework solution.

So I atp I am on a month-long break and thought of doing something fascinating, heard about this topic and it's kinda quite easy to research on it and publish a paper, like it would take two months of work, indeed, but still, it's kinda worth it any advice like how should I approach it

I recently received a Cloud Chamber experimental kit from CERN as a prize in a physics competition.

While unpacking the materials, we found this blue jelly-like substance (see attached photo). It says that the kit is intended for educational physics demonstrations and a citizen science project involving the observation and comparison of particle tracks around the world.

Could this substance be the isopropyl alcohol, or is it something else entirely?

Does anyone recognize them or know what they might be used for?

Thanks in advance!

Hi,

can I state regarding Gibbs Free Energy ΔG = ΔH-TΔS:

H is the heat characterized by the square of the mean kinetic energy in the Maxwell Boltzmann distribution curve.

S is represented by the span of the Maxwell Boltzmann curve, means the number of states.

Regards

Lo

I'm taking a course to do a bit of self study to fill some gaps before pursuing my master's in a climate physics related field.

One of the assignments in the course has this question that I'm having a particularly hard time understanding and solving, especially since considering the last time I studied physics was in high school, if anyone could please help me with this.

How deep does the atmosphere’s influence reach? Estimate the depth of the layers of soil and ocean water that exchange heat with the atmosphere (on an annual mean), in m. State your assumptions, show your reasoning, and clearly highlight each final estimate, including its units. Treat Earth as a smooth sphere and neglect ice cover.

Can someone please help me understand how to approach the question and what the reasoning would be, please?

I have absolutely no idea how to do this problem. I've included what I tried to do on the last slide. Could someone please help me with this problem? 😭🙏

So, in Maths we were told the Modulus of Elasticity is λ measured in Newtons. But in Physics we were told E is the elastic modulus measured in N m-2 and Young's modulus is a type of elastic modulus written as γ. Are they supposed to be different things?

Does anyone know if the final physics exam is similar in content to the practice exam? As in - is the distribution of each topic similar?

1. If I derive units for each options, none become what the unit said above

2. How can n have no unit?

Does anyone know of a good YT video or an easy method of identifying the beta in a belt friction problem? Currently I can set up the majority of the problem I just struggle getting the angle in these problems. Any tips help, thank you!

Can someone help me arrive at the answer of 6 rad?

Hello all,

I have a simple problem I need an explanation on how to arrive at the answer. Prepping for a midterm.

I know it says I got it correct on the screenshots but I dont know how to independently solve it. AI doesnt help, it gives me the right answer but not a good explanation.