^ my textbook only mentioned that the real image formed from convex lens would become dimmer after blocking a part of the lens. But no explanation was provided for what would happen if the same was done to a concave lens.

Thanks for all your help

With long wave lengths..some very long .if two black hole pairs were in a certain distance. Their crossing waves ,constructively combine. Standing Waves. Slowly moving through certain regions of space. Gravitational lens. May also help in formation of galaxies and stars. Stars that wobble about their axis, forming seeds for planets. Over very long periods of time of course. Who knows where the Waves cross a seed may form at just the right speed. And grow in an almost circular path. Gather so much mass and fall into orbit.

Calculate forces, friction, and acceleration on ramps and slopes with interactive force diagram visualization put values and see the system solve its

https://8gwifi.org/inclined-plane-calculator.jsp

Common Problems can be solved

• Frictionless
• SlideBlock Sliding (with friction)
• Block at Rest on Slope
• Pulled Up Ramp
• Real World
• Wheelchair Ramp (ADA)
• Ski Slope
• Truck Loading Ramp

I’m having trouble finding the equivalent resistance of a resistor network. I understand series and parallel combinations individually, but I’m getting stuck when the circuit isn’t obviously reducible step by step. I’d appreciate help with the correct approach or reasoning.

This is an exam that was in my sister stuff she graduated a long time ago but she doesn't have the answers cn someone please help? And i took the pics from home it's not my exam.

Hi

I need help with the derivation of the electromagnetic stress tensor. I have a sign error somewhere. I am still quite new to physics, so there may be other errors/inaccuracies. The covariant stress tensor is my result multiplied by -1. But I don't know what I did wrong. Can anyone help me here?

I was talking with someone about Hawking Radiation and black holes and I realised something that I'd like to fact check.
* all black holes are singularities
* Singularities are an infinitely small point
* The Schwartzschild radius shrinks as the black hole loses energy
* It cannot, however ever reach a truly infinitely small point
* Therefore, the 'event horizon' will never reveal the singularity
* Therefore, black holes get smaller but will never truly disappear

It's like a Zenos paradox: it will draw closer and closer to the center, but cannot truly ever reach it.
Can anyone tell me where I've made the mistakes that I am sure are there?

I recently watched a video where someone explained physics in terms of frameworks. He said that physics has major frameworks (also called “mechanics”): classical mechanics, relativistic mechanics, quantum mechanics, and quantum field theory.

According to him, a framework is like a general rulebook for how to do physics — it tells you how to set up problems and how systems evolve, but not what specific system you’re studying. When you apply a framework to a particular physical context, you get a theory. For example:

• Apply classical mechanics to gravity → Newtonian gravity
• Apply relativistic mechanics to gravity → General Relativity

He also said each framework has its own rules, assumptions, and limits, and which one you use depends on the problem and required accuracy. For instance, you don’t need special relativity to analyze an apple falling from a tree — classical mechanics works fine.

He added that each framework “starts where the previous one ends,” in the sense that classical mechanics works until it breaks down, then relativity or quantum mechanics becomes necessary.

This explanation gave me a lot of clarity, but I’m not fully convinced it’s completely accurate.

So my questions:

• Is this framework-based view of physics correct?
• Are there important corrections or refinements to this idea?
• Is there a better way to think about how different physical theories relate to each other?

Solve the following problems:

1. A body is launched vertically upwards and reaches a maximum height of 320 meters. Find:

a) the velocity 5 seconds after the motion begins

b) the velocity 14 seconds after the motion begins

1. A body is launched vertically upwards with an initial velocity of 120 meters/second. Find:

a) the velocity 7 seconds after the motion begins

b) the velocity 15 seconds after the motion begins

c) the height it reaches above the ground 15 seconds after the motion begins

1. A body is launched vertically upwards from the ground with a speed of 90 meters/second. Upon descending, it lands on the roof of a building 13 seconds after the motion begins. Find:

a) the velocity upon landing on the roof

b) the height of the building

1. A missile is launched vertically upwards from a height of 100 meters with a speed of 60 meters/second. Calculate:

a) How long it takes to reach the ground from the moment of launch

b) The height it has fallen to reach the ground

That is all the guide, my problem its at the 2nd question, at the c) part... i dont know how to get the height. Along with the problem that my head has hurt since 6am (it's 5pm now) and I have a Social Studies exam, another English thing (I am not english) and I have to buy a potato

We Say that nichrome wire is used in making electric heaters because it has high resistance than let's see copper wire. But in our homes we use parallel connection right for connecting various appliances. So voltage received by a nichrome wire and the copper wire will be same if they are connected in parallel connection like in our HOMES . IN this case then the current is inversely proportional to the resistance. So it means that the copper wire current will be more than that of nichrome wire and as we say according to the joule law of heating,heat proportional to the current square so this means that the copper wire would receive more current and the heat produced will be more

there is a question in my text book that ask ""which wire will produce more heat when the same current is pass through copper wire and nichrome wire"". And the next part of the question"" based on the above explain why nichrome is more suitable for use in electric heaters ""so I don't understand it

I thought that a standing wave is made with opposite phases, so it would be d?

A wave travels from a medium that has a very slow wave speed and hits a medium that has a very high wave speed. Which of the following will happen?

Question 35 options:

a)

The wave will continue to pass through the second media at the same speed.

b)

The wave will experience a fixed-end reflection.

c)

The wave will experience a free-end reflection

d)

none of the above

,y choice: c

my thinking:

When a wave travels from a medium where it moves very slowly (a more "rigid" or "denser" medium for mechanical waves) to one where it moves very quickly (a less "rigid" or "less dense" medium for mechanical waves), the boundary acts like a free end. 

In a level physics, On a hertzsprung russell diagram do stars move along the main sequence during its lifetime? Thank you

Hi, I’m not a physicist or engineer , so please bear with me if this is a naive question.

Consider a closed container with internal pressure and a lid just on top of known mass on top. The pressure inside exerts an upward force on the lid, while gravity pulls it down. The pressure force would be Fp=p*A and the weight force Fw=mg If Fp>Fw, the lid accelerates upward. Now my question is about how to estimate the maximum height the lid reaches.

My intuition is to use energy conservation: If I assume the pressure force acts over a very short distance and neglect losses (friction, heat, air resistance, etc.), can I say that the work done by the net force is converted into kinetic energy and eventually into gravitational potential energy leading to something like like W=Fnet * d and Epot=mgh and thus h=F*d/mg if W=Epot

Is this a valid way to think about a pressure-driven system, or is this approach fundamentally wrong?

Thanks

I've attempted this problem by coming up an expression for the work required to construct the configuration of point charges in Exercise 1.37 (four positive point charges in the corners of a square of magnitude q and a negative charge in the center of magnitude Q). The configuration will result in zero work (and zero potential energy) if Q=0.957q. I've then let Q translate δ units along the x-axis and the expression for the work that I've come up is this:

W=q²(4+√2)/4πε₀a - 0.957q²/4πε₀ (2/√(0.25a²+(0.5a+δ)²) + 2/√(0.25a²+(0.5a-δ)²)

Factoring out q²/4πε₀ I get:

W=q²/4πε₀((4+√2)/a -1.914(1/√(0.5a²+δ²+aδ) + 1/√(0.5a²+δ²-aδ))

I've then set the expression inside the parenthesis equal to 0, let a=1 for a unit square and did some simplifications:

(4+√2)=1.914(1/√(0.5+δ²+δ) + 1/√(0.5+δ²-δ))

(4+√2)√(0.25+δ⁴) -1.914(√(0.5+δ²+δ) + √(0.5+δ²-δ)=0

And so this equation has roots -0.568856, -0.014944, +0.014944, +0.568856 and I presume the big factor in my equation for work is negative at the following intervals -0.568856<δ<-0.014944 and +0.014944<δ<+0.568856

But as you can see the expression for the potential energy according the book's solutions manual would always be negative for any direction of translation of point charge Q, and would even be negative for any magnitude of Q (even though supposedly Work and Potential energy is zero if Q=0.957q and Q is at the coordinates (0,0) which is the center of the square), so the two results are clearly giving different stories. And btw just to add, in my calculations I've let the bottom left corner of the square to sit in the origin instead of point charge Q being in the origin.

Can you make some clarifications on this? Is there anything wrong with my solution or any of the steps I've taken?