Act Definition and 193 Threads

I was going through this paper where on page 5 they argue that in the given Poincare section: I am a bit confused by this statement. How does the given saddle point correspond to the black hole horizon and is it necessary that it acts as a source of chaos? Any explanation would be truly...

I am not against replacing fossil fuel, but we do NOT have a good solution yet. Why not build safer nuclear power plant? Or get into fusion power plant. I worked for a company as power of the Lawrence Livermore Fusion project back in 1979, still no result. Now they are fighting a losing battle...

I'm building a power hammer for a buddy's forge and am working through the design phase. We are going to use a 1200lb leaf spring to actuate the upper anvil. Pretty much got the mechanical design down, but having some issues with the selection of motor and control. The leaf spring we selected...

hello, i have a question about the forces that act on a rod at it's pivot point. the rod is free to rotate about the pivot point at the edge and it starts from rest parallel to the ground.the question is : when it reach to angle theta find the a] the angular velocity b] angular acceleration c]...

they said that Y is acting as the ground, what does it mean?

of course it would all have to be wired up correctly

Consider the following situation: You have 1 rectangular block lying on a table, and an identical block is placed above the block on the table. Now, this new block is constantly pushed to the right, right before it topples off. Consider the torque about an axis passing through the rightmost...

The normal reaction from the ground and from block m, the force of gravity are the forces I feel should act on the wedge but since the wedge is a perfectly rigid body and the pulley(which is massless) is attached to it so will tension also act on the wedge as well?

Given a force of tension with a string attached to the front of the box, do we take the force as acting with an angle to the centre of the mass of phi or theta? Explain please?

I have a fundamental question about the pressure and I am not sure if my reasoning is correct. Let's take an example of 7 stones shown below. They don't fall because the center of mass of each stone is falling right under the stone below. If I replace the same thing with a liquid, and we know...

I am confused about the problem. I thought operators do not act on bra vectors, and the problem is equivalent to ##a^{\dagger} \left | \alpha \right > = \left ( \alpha ^{*} + \frac {\partial} {\partial \alpha} \right ) \left | \alpha \right > ##. Then, strangely, ##\left < \alpha \right |##...

Since acceleration due to Newton's law decreases as the inverse of distance, it becomes very weak at large distances. Our Sun was unable to pull in matter in the Oort cloud in over 4 billion years. Above about 0.11 light years, using modified Newtonian dynamics equations, gravity decreases by...

Hello all After a lot of support from people like Dr.D, mfig and collinsmark I have finally understood the concept of Centriods and Centre of Mass. I am now trying to understand how a uniformally distributed force and a non uniformally distributed force acts on a shape. If I had an oddly...

can anyone explain me how O negative and COO negative acts as electron releasing group,I understood how alkyl groups acts as electron releasing group but I can't understand this

Summary: Robert Sungenis explains the sagnac effect Robert Sungenis, a well-known proponent of geocentrism, has authored a https://gwwdvd.com/what-allows-the-sun-to-revolve-around-the-earth/ in which he tries to explain the Sagnac effect as a result of Coriolis force (p.16-17), which he thinks...

A thought experiment. Two rigid, concentric rings, joined together by a series of lightweight elastic radial spokes. These rings and a heavy mass are approaching each other, such that in the frame of the rings, the mass is traveling along the central, perpendicular axis and will pass through the...

Hi, I am having trouble understanding the intuition behind the problem I attached. Work is the product of the force and displacement in the direction of displacement, so since the crate is moving horizontally from A to B why isn't the displacement AB = 6m? Thanks in advance

Acceleration of a rotating link has two components,Tangential (change in the direction) Radial (change in the magnitude). Why the direction of Radial acceleration is considered towards center (Centripetal)? what about centrifugal?

I am looking for an optical piece that can act as a mirror when the angle of incidence is close to normal (90 degrees) but acts as a see-through glass when the angle of incidence is less than 60 degrees? Alternatively it can be a filter placed in front of a mirror that passes a lot of light at...

I know this is kind of a dumb question but please forgive me it's been awhile. Is it enough for a particle to merely "feel" an external force F to state that "F is acting on the particle"? ie if the particle was confined in a potential well and experiences F but does not move. or does...

How do the components of the stress-energy tensor act on gravity regarding a) the FRW-universe? b) a solid ball? In a FRW-universe ##\rho + 3P## determines the second derivative of the scale factor. So, there are no non-diagonal components. Just theoretically, if the perfect fluid was...

Homework Statement Which of the following combinations would act as buffered solutions? a. HCl and NaCl b. CH_3COOH and KCH_3COO c. H_2S and NaHS d. H_2S and Na_2S Homework Equations none really... The acid needs to be weak and the base strong though. The Attempt at a Solution HCl is one...

If you were to have some way to remove plasma out of a tokamak or stellarator, how would it act? I realize there's basically no way to actually remove plasma from those machines, but I'm curious how plasma would act in the actual atmosphere. Would it act like a plasma cutter? Would it stay...

So I have been learning about measuring nuclei radius using electron diffraction, using sin(theta)=1.22lambda/d, doing some research I found out that is the equation for circular aperture diffraction but I don’t really understand how a group of nucleus can act as a circular aperture. Also is...

All, I hope this is in the right forum. I'm a bit embarrassed that I cannot make sense of this graph. My question is this: When looking at the graph, should you ONLY be reading data points from the two lines -- but also reading the lines independently? I am at a loss why the atmospheric...

greeting How exactly the electric force acts .The definition of force is In physics, a force is any interaction that, when unopposed, will change the motion of an object. as the electron circulates around the nucleus of the atom because of that I do not see how that force acts .

Is there only two trusses? As shown below:

Homework Statement It's a synthesis, dedicated more to carbonyl reactions. However, there is this step where you deduce the structure of an elongated terminal alkyne and then they tell you to add 1. MeMgBr 2. Formaldehyde. Homework Equations Usually organometallics are used to transform the...

I was passing time by Googling the properties of the sun (temperature, mass, etc) and got to wondering what lies at the center of stars. I found out its plasma under roughly 340 billion atmospheres of pressure. I realize Boyles law may not be strictly meant for plasmas, but using it I...

can light collectively or individual photons act as a medium for propagation of sound waves?

What is the x-intercept of the line that passes through points (-3,7) and (6,4) in the standard (x,y) coordinate plane?

Black hole or more correctly the event horizon will not let anything past through it, from inside to outside, ok. But then we get to a particle with zero mass eg. photon. How can gravity act on that particle, surely for gravity to act there must be mass? Or does it act on the electromagnetic...

So when a conductor in complete circuit is placed next to a moving magnetic field, current in the conductor is induced and the induced current again produces its own magnetic field. So does this new magnetic field act on the conductor? It's the same as the question in the title. Is my concept...

For a particle undergoing a constant velocity circular motion. I thought friction always acted in the direction of motion which would be in the tangential direction.

What is the sum of all the even integers between 1 and 101? Is there an easier way besides using the formula: (B-A+1)(B+A)/2? It just takes too much time.

Assume that (x-4) is a factor of 2x^2-4x-z. What is the value of z? How would you set it up to use the foil method?

Before Joseph paints his house, he pours blue paint into 2 buckets of different sizes. He notices that the volume of the larger bucket is 3 times the volume of the smaller bucket. At the end of the day, Joseph estimates that the larger bucket is 3/4 full and the smaller bucket is 1/3 full/ He...

Joan is riding her bicycle along a track at 15 miles per hour. Anthony, who is ahead of Joan on the same track, is riding his bicycle at 12 miles per hour. If it will take Joan 5 hours to catch Anthony at their current speeds, how many mile ahead of Joan on the track is Anthony? How would you...

What is the x-intercept of the graph of y = x2 – 4x + 4? How would you foil this?

Hello! I'm an Engineer by profession with less knowledge of physics, so please be basic with me. After recently being intrigued by the double slit experiment, I started to read more and more about the same. At most of the places, it says that as soon a sensor is kept near one of the slit to find...

Homework Statement Two forces act on a 55 kg object. One has a magnitude of 65 N directed 59 degrees clockwise from the pos. x axis. The other has magnitude 35 N at 32 o clockwise from the pos. y axis.What is the acceleration of the object? The answer is given as 1.1 m/ s squared, (I got a...

I am really struggling with one concept in my study of differential geometry where there seems to be a conflict among different textbooks. To set up the question, let M be a manifold and let (U, φ) be a chart. Now suppose we have a curve γ:(-ε,+ε) → M such that γ(t)=0 at a ∈ M. Suppose further...

We know Earth grounding is huge electron sink. But the Earth is not portable, what material can absorb lots of electron inside or on surface? Maybe the supercapacitors already use it as its cathode? and what material dislike electron and push electron away? thanks

Organic Chemistry question! Is 9-BBN too sterically hindered to even react with internal alkynes or alkenes? (to do hydroboration)

I'm studying for the ACT and this was one of the practice test problems. The book does offer an explanation for how to get the answer but it isn't very detailed and I still don't know what I'm doing wrong. Homework Statement The larger of two numbers exceeds twice the smaller number by ##8##...

I'm reading through my quantum physics lecture notes (see page 216 of the lecture notes for more details) and under the ladder operators section there is a discussion of the expectation value of ##L_x## for a state ##\psi = R(r) \left( \sqrt{ \frac{2}{3}} Y_{11} - \sqrt{ \frac{1}{3}} Y_{10}...

My question is simple though I fear the answer may be complex: What does the act of observing do exactly? I hear observing does some unexpected things in quantum (I wouldn't doubt there is a religon based on it). I am a math major with a love of physics though I'm not that versed in it so...

Hi, I'm working with a magnetic levitron project and I've borrowed a professional levitron to see how it works. When I remove the back cap, unexpectedly I saw a square shaped magnet instead of ring magnet. But it acts like almost a ring magnet. I'll explain the difference with images below. At...

Homework Statement [/B] A 10kg bowling ball is moving with a velocity of -3m/s. a) What is the momentum of the bowling ball? b) What impulse must act on the bowling ball to bring it to a stop? Homework Equations momentum=mv impulse=ΣFΔt ΣFΔt=mΔv The Attempt at a Solution a) momentum = mv...

A question that has been bothering me for a while, is why are we as a physics community so fine with remormalization in QFT? Experimentally (QED especially) the field is VERY precise, however, looking at the mathematical side of renormalization, it doesn't look... very logical. We get divergent...