Apply Definition and 508 Threads

I'm an undergrad aspiring to be a candidate for a MS in Medical Physics. I came into freshman year as a physics major, did poor in my first physics class, and changed my major to business. After realizing that was a mistake after a year, I switched back to physics. My Major GPA is a 2.0 after 10...

Dear Sirs, when i lifting, i want to check the strength of structure, but i don't want to check padeye, because it's standard, but i must model padeye to apply force, so how can i apply force to padeye, but padeye just a reference body for my calculation, anyone help me pls, thank you so much

Homework Statement A tuning fork has a frequency of 440 Hz. A) What is the size of one quantum of energy of vibration? B) To approximately what temperature would the fork have to be cooled before equipartition would cease to apply to its thermal motions? Homework EquationsThe Attempt at a...

(I am not very sure if this is a high-school level question or a undergraduate level question. Sorry.) Does our normal differentiation rules, like the product rule and quotient rule apply to vectors? Say for example, differentiate ##r \times \dot r## ##r## is radius vector, ##\dot r## is the...

Homework Statement A bullet was shot at 40m/s Elevation angle : 37° Bullet mass = 0.01 Kg Question : how much work is done by the force of gravity to the bullet since it was shot until it reaches the ground again Homework Equations mgh = E.Pot 1/2mv ^2 = E kinetic The Attempt at a Solution...

I am now taking optics class at my school. Fermat principle can be applied on mirror of course. Then what about Concave mirror? According to the calculus of variation. the optimized path(actual path of the light) should be the shortest path. but in the concave mirror case, it goes through the...

Homework Statement A spring (k = 500 N/m) supports a 400 g mass which is immersed in 900 g of water. The specific heat of the mass is 450 J/kg and of water is 4184 J/kg. The spring is now stretched 15 cm and, after thermal equilibrium is reached, the mass is released so it vibrates up and...

For example, if I have a magnetic field perpendicular to some surface and I change this magnetic field with constant speed, how do I calculate the Electric field at any point on this surface, since ∫E⋅ds=k, where k is some constant, could be done with many different vector fields.

Hi everyone. In reading some popular textbooks I noticed that in (maybe) most of GR and SR we don't encounter situations where we can use wedge-product and differential forms. However, these things are presented to us in most of the textbooks. But... if most of the books present them, it means...

For static electric fields? does it apply also for a generic electric field? Let's say, moving charges inside a closed surface? If there are charges accelerating in a closed surface a part of the electric field is due to the charges, and a a part is due to the fact that the charges acceleration...

Hello, I am doing a physics exam, where I have chosen to create a Brachistochrone curve, and perform various tests on it. Furthermore, I also have to write a physics report, containing the theory behind the curve, but I am not 100% sure what some of the theories behind the curve are. I suppose...

I am only aware that the formula has to do with entropy/thermodynamics. I could really use the help on how it applies in physics and what the formula is really about.

From Odum (Father of modern ecology) Ecosystem follows the laws of termodynamics 1st law 2nd law The way the laws have been put it looks alright but they are valid for closed systems only which ecosystems are not. However according to wikipedia apart from having a closed system there are...

< Mentor Note -- OP deleted this original post, which has been restored by the Moderators. Thread will remain closed. > same professor. different topics from what i can make out - one more linked to partial differential equations, analysis, one using lagrangian/ hamiltonian dynamics and...

I'm reading a textbook that says: "The directional derivative in direction ##u## is the derivative of the function ##f( \mathbf x + \alpha \mathbf u)## with respect to ##\alpha##, evaluated at ##\alpha=0##. Using the chain rule, we can see that ##\frac {\partial}{\partial \alpha} f( \mathbf x...

Do laws of physics apply below the event horizon? It appears as if black holes had such gravity as to have an escapr velocity higher than c, which means that things are pulled inwards at higher speeds than the speed of light. Or am I overlooking something?

If everything goes right I am in my last year of my physics program in my university. I want to do research, I did a short internship at CERN and I would like to work there, and I know that for that I need to get a masters or a phd. The thing is that I am not sure to which university should I...

Hey! :o Let $\text{Val} = \{0, 1\}^8$, $\text{Adr} = \{0, 1\}^{32}$ and $\text{Mem} = \text{Val}^{\text{Adr}}$. The addition modulo $2^8$ of two numbers in binary system of length $8$, is given by the mapping: $$\text{add}_{\text{Val}} : \text{Val}\times \text{Val}\rightarrow \text{Val} \\...

Hi all, I am looking for advice on what physics graduate programs to apply to. My original list was: University of Maryland - College Park Harvard University Columbia University Caltech Pennsylvania State University of Illinois - Urbana-Champaign Colorado University - Boulder UC-Barbara...

Hi! I apologize in advance if you get a lot of indecisive kids like me putting spammy requests for first year university application advice and if I'm breaking any rules by putting this thread here etc just let me know. Anyway I'm an aspiring physicist in my last year of secondary school in...

Hello, I would like to know what positions I can apply for based on my background. I have a bachelor's degree in computer engineering, and a master and PhD degrees in electrical engineering with specialization in wireless communications. My initial plan was to get a position in academia. But...

Hey! :o To check the convergence or divergence of series there are the following tests: Trivial test If a series $\sum a_k$ converges, then the sequence $a_k$ is a zero-sequence. With this test we can just prove the divergence, but not in general the convergence of a series. \ Ratiom...

Hello! (Wave) I am reading the proof that if the function $v$ is subharmonic in $\Omega$ then $ H_{B_0}[v]$ is also subharmonic in $\Omega$. ($B_0 $ is a ball in $\Omega$) (We say that the function $v$ is subharmonic in $\Omega$ if for every ball $B \subset \Omega$ it holds that $v \leq...

Suppose we have a body of finite size which can be translated, rotated, compressed and stretched. We have every information about the body. We have its dimensions and everything. We have its mass and density. But, since I'm here talking about a completely generalized version, so we have variable...

A Moving Clock runs slow. But, If time t has elapsed in the S frame, does SR apply to a clock moving with speed u in the x-direction in the S frame, relative to the S frame? Or does SR apply only when the clock is in another reference frame S' moving in the x'-prime direction, given that...

Hey everyone, I am wondering if anyone can give me an idea of which physics PhD programs I should be looking at. I am a bit confused about which programs I would be competitive for. I have read things about how ranking and "minimum gpa" requirements are misleading when it comes to admissions...

I have been curious for some time, does the incompleteness theorem of mathematics have any consequences in physics? In order that I may understand your response you should know I'm was a senior math major at the university when last I was in school and my only physics background is the standard...

Firstly I'd like to apologise as I know this is a pretty common topic to post questions on! Basically I recently graduated with a first class (72% average) from the University of Southampton (Russell group, but obviously not Oxbridge level) and am planning to spend a year out applying to PhD's...

Homework Statement Homework Equations Formula for Area of a retangle : A = L x W Pythagorean theorem: A2 + b2 = c2 The Attempt at a Solution So I am pretty sure I did it correct but I just want to be 100% certain I will get this right, By the way its a picture cause I found it easier to...

Homework Statement "Under mild continuity restrictions, it is true that if ##F(x)=\int_a^b g(t,x)dt##, then ##F'(x)=\int_a^b g_x(t,x)dt##. Using this fact and the Chain Rule, we can find the derivative of ##F(x)=\int_{a}^{f(x)} g(t,x)dt## by letting ##G(u,x)=\int_a^u g(t,x)dt##, where...

Let's say I have multiple spin systems (atoms in a protein) in a solution of water and the spin systems are all producing a magnetic field \mathrm{B_{loc}} that affects nearby spin systems. Will the fluctuation-dispersion theorem apply to the force generated by a spin's magnetic field...

I have a certain set of problems (i.e. https://www.math.ucdavis.edu/~kouba/CalcOneDIRECTORY/limcondirectory/LimitConstant.html), where many problems are in an indeterminate form ($\frac{0}{0}$) but if we apply L'Hopital's rule it yields an incorrect answer. Instead, I have to simplify the...

I want to be able to build or find a mechanical device that can apply very low force/pressure to a material. I have considered using a stepping motor with a flat needle tip but I can't think of a way to make this delicate enough to not destroy my sample. I am wanting to apply forces in the range...

Homework Statement Apply Ohm's law and the nature of parallel circuits to determine the total current in a parallel circuit with three resistors: 3Ω, 6Ω, and 9Ω, respectively. The total voltage in the circuit is 12V. Explain your reasoning. Homework Equations [/B] Ohm's LawThe Attempt at a...

Homework Statement The elliptical orbit of a comet is shown above (hidden document I apologize but easy to picture). Positions 1 and 2 are, respectively, the farthest and nearest positions to the Sun, and at position 1 the distance from the comet to the Sun is 10 times that at position 2. What...

Einstein's STOR states that if I was in an upward accelerating elevator I would not be able to tell if the weight I would be experiencing was due to acceleration or gravity from my frame of reference. This identical appearance idea work for expansion also? It has been stated many times that...

I am doing my exchange studies in Sweden and have applied to two internship offers at Volvo. However, I've heard that the competition is tough (especially for non-native speakers). Application results are only for the next month. Should I apply to other internships/thesis placements across...

I really like Mechanical Engineering. I'm now at the second year of my undergrad and I'm now taking some specific courses in engineering - after a whole year of calculus and physics. I think it's the broadest engineering, and I'm an admirer of the aerospace industry and would like to work with...

I apologize in advance for this dumb question, I think I know the answer but I just want to be sure.A photon has energy E = pc = hf Do the Energy-Momentum transformations: apply exactly to photons? Or must we introduce certain corrective terms? Let's say all this takes place in free space.

It seems that historical events are the same every day. If the future affected the past wouldn't history books change everyday by themselves? Is it possible that history does actually change but we don't realize it because our memories change too?

What I have done so far... Is this correct so far? If not, would someone be able to provide an explanation as to how to solve this? I am not sure if I am going in the right direction. Thank you

Was just wondering is it only possible for magnetic attraction? because the force increases exponentially with decreased distance, or can it be used for repulsion. It's blatantly obvious that magnetic repulsion is a lot weaker than attraction, by a 10% margin. hence why repulsion is weaker, but...

Electrons have a theoretical rest mass. They can move at varying speeds through space, unlike photons. They ehxhibit quantum-characteristics in their behavior. If an electron collides with, say, an atom, does conservation of momentum apply in the classical sense or does measurable mass (an atom...

Hi! I currently live in New Zealand and am in Year 11/Grade 10. Naturally as this is a physics forum I have been interested in doing physics degree when I leave high school. If I were to stay in New Zealand for undergraduate I would be going to the University of Auckland. What are your thoughts...

Hello PF members, In Newtonian perspective, applying a force to a object like ball causes it starts to moving and getting more speed and more energy. Do photon apply a force to the electron when it interacts with the atom and electron absorbs it? It seems electron gets more energy and goes to...

A person of 60 kg is holding on a rope of 3m while standing on a the ledge of a building of height 7m. The rope is fixed to a point at roughly eye level 3 m from ledge. The person walks off the building and is swung in a vertical circle. If the person let's go at approximately the same height he...

How can a transformer increase the voltage yet lower the current? Are the equations P=VI and V=RI contradictory? Thanks in advance and sorry if I made any english mistakes.

Can we apply friss equation to find field strength at the receiving point for space wave propagation?

Hello! (Wave) I want to solve the following linear programming problem: $$\min (3y_1-y_2+2y_3) \\ 3y_1+2y_2-y_3 \leq 9 \\ 5y_2-y_3 \leq 1 \\ 4y_1-y_2 \geq 1 \\ y_1+y_2+y_3 \leq 3 \\ y_1, y_2, y_3 \geq 0$$ In this case we use the $M$-method.The canonical form of the problem is the...

I completed high school, and received diploma in '09. Currently I am in adult school advancing my high school credits. I am able to apply as either an Adult or as a Current Student. But, I don't know which I should choose; I have been told that I am able to apply as either, and each has its...