Classical Physics

This has been a common trope running round most of the pop-science channels on Youtube over the last year or so. I won't name names but I guess some of you know some of the channels in question. It starts with a box with N particles randomly dotted around inside it. The presenter then changes the cartoon to one where all the dots are shown on the left hand side of the box and states 'Statistical Mechanics says that all random configurations of particles are possible, therefore sometime eventually this low entropy configuration will occur, therefore the 2nd Law only applies sometimes'. Leaving aside the macroscopic shift in centre of mass that shows dereliction …

1 law cant create energy. ok but you can give energy to a ferromagnetic and magnetize it. then magnetize as many ferromagnetic material as you want, and not diminish the magnetic field of the 1st one you had. I don't understand how no loss and how that is not considered braking the 1st rule

I just finished learning about vector components in my class, and I was hoping to understand the vector notation i hat, j hat, and k hat, but our book doesn't use that notation and gives an unsatisfying description of what the bold units stand for. Can someone please give me an overview of what they mean, and why they are without units? Thanks...

The physics book I'm using gives two examples where one is a third law pair and the other is not. What is the reasoning that this example is not a third law pair: "The upward normal force from the table and the downward force due to gravity are not an action/reaction pair of Newton's third law."

know that objects with the same surface area but different densities fall at the same speed in a vacuum. However, there is actually a big argument between me and my girlfriend, at the point of I feel like strangling her to death. I say heavier objects do fall faster (I provided calculations). She (appears) to think that this is nonsense and am full-of-shit and she knows better because she knows more about the topic and am just a uni student (She was my lecturer, before we started dating. Now shes just my bitch) I dropped a piece of paper, and a piece of cardboard with similar SA. The cardboard fell much faster. I could explain this by stating that heavie…

So the electrical engineer who was doing this stuff for 50 years is wrong. The electrical engineer who solved computer crashes created by static electric discharges is wrong. Electricity only exists when a positive and negative charge make a connection. That negative charge cannot be created without creating a positive charge elsewhere. So when we prevent static electric damage, earth ground appears nowhere in that solution. Static electric prevention is always about making that connection from positive to negative charges via a path that is not destructive. It is even a standard experiment in physics class. Using Styrofoam balls to repel and attract. Ea…

Ive read that even a little thimble-full of matter from objects like nuetron stars weigh an ungodly amount on Earth. My question is, can this matter even exist on Earth? Is there a limit to how dense an object can be on this Earth? Thanks for any info

This was performed in my high shool Physics class. I have contacted the show. You seen it on All In The Family, The Honeymooners, and even on Bill Nye the science guy, and performed in grammer school science classes. This practice of lifting a chair 3 steps back from the wall was passed off as medical fact that a womans spleen was stronger than a mans because she is designed to have children. This was a trick created by a woman. If a man & woman are the same height, the mans feet are longer, this creates a greater space between the wall and the body compared to the woman, so when he backs up 3 steps, he is on his tippy toes, compared to the woman who is flat …

Hello, I'm a computer programmer and although I do have education in classical physics including electrical courses and as well as practical experience with assembly and testing of UV radiation equipment, their power supplies and overall wiring, I'm surprised to realize I have no idea what is the purpose, derivation (experimental origin) and the meaning of Maxwell's equations as I can not recall to have used any of them for anything. This realization happened when I was supposed to simulate - model and visualize in 3D - the simplest electromagnetic interaction there is, between electric and magnetic fields from only two electrons/positrons, including the tracing o…

e are living in an accelerated world: have a look at the picture below We know that the distance between the poles is D. What appears to us is d4 larger than d3, larger than d2, larger than d1 etc If you are looking toward a motorcycle coming at you at constant velocity, what will you see? You will see the bike travelling d1 in say 1 sec, d2 in 1 sec, d3 in 1 sec, d4 in 1 sec. IOW you will see it coming slowly from far away, then progressively accelerating and suddenly wizzz in front of your eyes, then vanishing slowly to the horizon on the other direction. Like this: (link to a FB page with a Kawa at high speed) https://www.facebook.com/Kawasakiconta…

Consider this a laser beam fired between points A and B. Consider an infinite -1 observers, viewing the laser beam from all angles above below, sideways etc etc. Each observer receives photons onto their retina from the laser beam. So the light just doesn’t travel in a straight line but is seen by all observers at every angles. Does this mean that an infinite-1 number of photons travel in every direction to make the beam visible???????

Dear Forum, I have run across a very interesting machine that I was wondering if someone might could comment on. It is a version of the Sterling Engine, that uses a turbine instead of a piston. They have just completed phase I testing, and say it was successful. Here is a link: http://www.kendersolar.com/ This describes the technology: http://www.kendersolar.com/index.php/The-solar-technology-of-the-Kender-Engine-Phase-1.html They claim that the energy extracted by the solar panel produces more energy than what it takes to drive the compressor to circulate the helium, and results in: "The system produces 39 kW of power (47 kW by the turbine, less 8 kW …

Something is really bothering me about magnetic field. So I know we use magnetic field lines to represent the intensity of the magnetic field. For example, the closer they are the stronger the field. However when we look at iron filing aligning in a magnetic field, we see them grouping into distinct lines, almost imitating field lines, but this must mean that the field is weaker between the lines and stronger on the field lines, which makes no sense to me. Can someone explain why the filings form distinct lines and why there are gaps with no filings in them?

Hello Dear Scientists, I kindly ask for your patience with me as Im no scientist, but I'm learning. I have a few questions here. Today I came across this video on the BBC: http://www.bbc.com/earth/story/20161021-why-there-could-be-many-copies-of-you The scientist in this documentary says that the cosmos is eternal. But it cannot be according to basic scientific theory and understanding: a) Matter cannot be created. It is finite. Do we agree on this, or have I misunderstood the 1st law of Conservation of matter: According to the law of conservation of matter, matter is neither created nor destroyed, so we must have the same number …

Hi guys, This is probably a question that has been asked before, but I just thought about it a few days ago and couldn't quite figure out if I have the right answer. If we look at a sailboat, it's working in a quite "simple" way: The wind pushes the sail and gives the boat momentum. The wind, however, is not something that we can say originates from a specific POINT. It's the movement of air molecules. What would happen if I stick a very powerful fan on the rear of the sailboat, facing the sail? Would my sailboat be faster? When I was thinking about it, the first thing that came to my mind is a comparison to a situation where I'd be pushing the boat from …

How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc. So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?

Ok I have a question about a spinning circle. How can a circle spin round? I know it sound weird but I while on a merry-go-round it hit me that the outside of a circle has a bigger circumference than further in the circle, so wouldn’t the edge of the merry-go-round have to be moving faster than the centre of the merry-go-round because it has a bigger distance to travel than the centre does. To try and put it more simple, if the circumference of a circle is 10cm then further in the circle there would be a circumference of 5cm but for the circle to do a complete rotation in say 60 seconds, the outside of the circle would be going at a speed of 10cm per minute but inside…

If I know the distance an object travels from point A to point B, that it starts from a stopped position and the time that it takes to get from point A to point B, how can I calculate the top speed at point B?

The fact (or is it?) that a heat engine will never attain 100% efficiency in transferring heat into work, even under ideal conditions, really annoys me. Imagine this: A cylinder-piston arrangement is made out of a material that is non-thermal conducting, and there is no friction or air resistance between the piston and the air/walls. Now suppose that the cylinder contains a pocket of air that is at the same pressure as the air outside. The pocket of air is quickly heated by an external source so that the temperature in the pocket rises, thus increasing the pressure. This pressure difference will cause the piston to accelerate outwards, expanding the volume inside the …

Isn't that a bit oddly written? Seems like a popularization. Newton's First Law (also known as the Law of Inertia) states that an object at rest tends to stay at rest and that an object in uniform motion tends to stay in uniform motion unless acted upon by a net external force. If it is just a popularization, I'm unsure why it had to say "tend" when it's more accurate to say "object at rest stays at rest and that an object in uniform motion stays in uniform motion unless acted upon by..." Otherwise, it implies that an object doesn't always stay at rest or in motion even if it weren't acted upon by an external force. Plus it says nothing about an int…

I'm having a discussion with several folks about the results of a head on collision of two similar vehicles that have about the same weight and crush properties. I stated that if both vehicles collide head on, at 60 MPH, the impact force and damage to each vehicle would be roughly the same as hitting a solid unmoveable object at 60 MPH, because each vehicle absorbs roughly 50% of the damage. They claim that because both vehicles are traveling at 60 MPH, their combined speed of 120 MPH would increase the damage to twice what it would be if the vehicle hit a solid object at 60 MPH. How can I explain this to them?

Why should the gas inside a cathode ray tube be a low pressure in order for the current to flow? (i.e the cathode rays) Why don't the rays appear when there is a gas at normal pressure inside the tube?

Hi everyone i found this video on youtube saying that this substance has magical properties, one of them is to not have a reflection on the mirror... i tried to find where is the trick but didn't notice anything strange.. So what do you think?

Okay, so i just watched the mythbuster episode with the killer deck myth. i know it can't actually kill people but i thought "hey that would be a cool thing to do" and since i only have two urgent things for uni i done some solid practice at it. i must be doing something right because my plasterboard wall is covered in tiny cuts everywhere and my mum looks like she's going to rip my throat out via my nostrils. through experimentation i know its all about spin and most of that comes from the wrist but how fast do these things have to be spinning to cut half a centimeter into plasterboard(drywall in the US i believe)?

Now, if I am not mistaken, from what I know, the axis of rotation of a body usually goes through the center of gravity of a body. Also, the position of the center of gravity, if I recall correctly, does change when the position of the body of the living being or object in question changes. Well, just to make sure, I must ask: would the location of the axis of rotation change if the position of the center of gravity changes as well?