Accelerating Definition and 654 Threads

What is the fundamental rationale for why particles moving through the Higgs ocean would only interact if they are accelerating?

Homework Statement Q1> there is a cube like jar of water kept at the surface of a lift which is moving with an acceleration of a in upward direction. jar is filled with water. There is a cubical block of wood floating on it's surface. It is slightly pressed and released. find the time period...

If an object on a horizontal platform is moving at a constant velocity of 10m/s, and then begins to accelerate, what happens to the force of friction? Some people are telling me that the force of friction decreases and therefore the object accelerates... HOWEVEr.. force of friction =...

Homework Statement a 12 kg meteor experiences an acceleration of 7.2 m/s^2, when faling towards the earth. How high above the Earths surface is the meteor? Homework Equations mass of earth= 5.98x1024 kg radius of earth= 6.36x106 m g=G*MEarth/r2 r=√G*ME/g The Attempt...

Current is simply flow of charge, and acceleration of charged particles produces EM radiation. Then if we bend a wire,charges(current) would be accelerated as they change direction,then a bent wire must radiate.Is it true?

Homework Statement The figure shows two 2.5 kg blocks connected by a rope that has a mass of 450g. The entire assembly is accelerated upwards at 7.4 m/s^ What is the tension at the bottom end of the rope, near block B What is the tension at the at the top end of the rope, near block A...

Homework Statement A pendulum on Earth consists of a mass m suspended on a massless spring with equilibrium length d and spring constant k. The pendulum point of support is moving up with constant acceleration a. What is the Hamiltonian of the system? Derive the Hamiltonian equations...

Can anyone explain it to me? Why does the front end of the car lift forward when it is accelerating forward? Is there a torque that is causing this lift?

We all know the definition of a rope between two identical accelerating spaceships and how that rope will break assuming they both accelerate with the identical same velocity (as defined from a observer on Earth for example). And it makes sense, thinking of stress. But how do I define a Lorentz...

my community is debating the wisdom of putting a roundabout at a busy intersection. we currently have a 4 way stop, and traffic backs up. How much gas is used to accelerate your average 4000 lb vehicle from a dead stop ( as required by stop sign ) to 20 mph (apx speed to go through a...

Homework Statement Two wooden crates rest on top of one another. The smaller top crate has a mass of m1 = 22 kg and the larger bottom crate has a mass of m2 = 94 kg. There is NO friction between the crate and the floor, but the coefficient of static friction between the two crates is μs =...

In this thread I would like you to add some more detailed information on what the people behind the new physics prize have actually found, what the interpretation is and where the relevant papers are. The redshifts of supernovaes of type 1a are redshifted in some peculiar way that is...

Can the kinetic friction be in the direction of acceleration? I am thinking of the example of a box on a flatbed truck accelerating to the right from rest. The box accelerates to the left due to the inertial force as seen by an observer on the truck where the kinetic friction is opposite to the...

I'm not sure how strong the evidence is for this but I found it interesting: "Now, a new theory suggests that the accelerating expansion of the universe is merely an illusion, akin to a mirage in the desert. The false impression results from the way our particular region of the cosmos is...

Homework Statement Find the force necessary to give a proton an acceleration of 10^19m/s^2 when the proton has a velocity ( along the same direction as the force) of 0.9c Homework Equations p=gamma * m * U F = d/dt [gamma * M * U] F=gamma^3 *m*a The Attempt at a Solution initial momentum...

the way I am understanding how voltage works is how fast one coulomb is passing a point. so if i push more electrons passed a point, it actually gives it a higher voltage? that and, if i have a screen with a positive potential across it and an electron stream flowing towards it, would the...

Hello, I am wondering, if I am sitting on my chair, here at home, planet Earth, am I accelerating (in GR)? Does the tangent four-vector u to my worldline obey the equation \nabla_{u} u = a or instead \nabla_{u} u = 0 ?? and if the first one is correct, is the four-vector a constant?

Homework Statement A huge SUV of mass 2300 kg can accelerate from 0 to 60 mi/h in 9.0 s. What force does the road exert on the SUV? V0 = 0 V= 60mph or 26.8224m/s M= 2300kg t=9s Homework Equations F=ma The Attempt at a Solution a= (26.8224) / 9 = 2.98 Fx = ma = 2.98*2300 =...

Hi, Please consider: At time zero a spaceship takes off from Earth and keeps traveling under constant acceleration. From Earth's perspective, the spaceship's speed keeps increasing but never reaches c. Also from Earth's perspective, the clock on the spaceship keeps slowing down and...

Homework Statement A wheel of radius b rolls along the ground with constant forward acceleration a0. Show that at any given instant, the magnitude of the acceleration of any point on the wheel is (a0^2 + (v^4 / b^2))^(1/2) relative to the center of the wheel. Here v is the...

Hi, Say I have a machine with a mass of 10 kg at rest (with respect to an observer) in frictionless, gravity-free space. This machine now takes 1 kg of itself, and using the energy of 1 joule, flings this 1kg chunk toward the observer. How do I compute the final velocity of the remaining...

Hey guys, I have a couple of questions regarding X-rays and how they are produced. 1) Is an X-ray an electromagnetic wave or a photon? 2) Why is it that when the electrons collide with the anode in an x-ray tube, X-rays are emitted and not any other electromagnetic wave/photon? 3) When the...

Hi, Let us assume that Hubble's Constant H is really constant. Therefore: a' / a = H where a is the scale factor. The solution to this equation is: a(t) = exp(H t) This equation describes an accelerating universe with deceleration parameter q given by: q = - a'' a / a'^2 =...

When the an object is accelerated and when the velocity approaches the speed of light, its mass increases exponentially the force required to accelerate the object increases exponentially. So it cannot be done. Fine. But what if I travel in a spaceship with A LOT of fuel and the spaceship is...

Does quantum theory predict that an accelerating electron emmits a photon?

Dear all, I am searching for some far objects in the universe (anywhere!) that have the lowest acceleration from us. Take it for example as an unusual number like 10^-250 Is it too strange? Do we have such things in the world? I tried to use Proxima Centauri but it is not as slow as I...

Homework Statement (Kleppner & Kolenkow - Introduction to Mechanics - 2.17) The first attached image shows a box on an incline which is accelerated at a rate a meters per second squared. \mu is the coefficient of friction between the box and incline surface. The questions are in the image...

Homework Statement A block is placed against the vertical front of a cart as shown in the figure. (see attachment) What acceleration must the cart have in order that block A does not fall? The coefficient of static friction between the block and the cart is u_s. Homework Equations f_s=u_sn...

I’m new to these forums and as a matter of personal curiosity, and as someone who can’t follow the math behind the basic concepts, I have a few questions. The first set have to do with the accelerating expansion of our universe. A) Does this acceleration affect the inflationary model of the...

Homework Statement http://img823.imageshack.us/img823/5238/immaginelq.th.jpg Uploaded with ImageShack.us What horizontal force F must be constantly applied to M so that M_1 and M_2 do not move relative to M? neglet frictionHomework Equations The Attempt at a Solution Since M_2 is not moving...

http://scienceblogs.com/principles/2010/02/physics_quiz_accelerated_twins.php The answer, they claim, is that Alice ages more than Bob. But say this were true, it would also mean that of two synchronized clocks placed on opposite sides of the earth, one at sunrise, and the other at sunset...

If accelerating charges emit light. Then would this imply that mass less particle could not emit light because they cannot accelerate?

hey guys, I am new here and this is my first post, but i need some help. the concept i am trying to explain mathematically is the acceleration a skateboarder (150kg) will have going down a hill (5 degrees bellow the horizontal) completely straight (2 dimensional), including air drag. to make...

So apparently SR can handle non-inertial reference frames, and there are supposedly some interesting effects that come about, like non-constancy of the speed of light. I was wondering if anyone knew where I could find a treatment of accelerating frames in SR (like a textbook)?

I'm free-falling towards a planet. Inertial or not? I suppose this is a postulate of general relativity isn't it? When I'm studying special relativity I would say Non-inertial, but then if I think about how I cannot really tell if I am accelerating or just traveling a constant...

I have finally been able to derive the velocity of a light pulse, according to an accelerating observer. The reference frame for the accelerating observer is taken to be the CADO reference frame, which is the only choice that I consider to be acceptable. The CADO reference frame is described...

Homework Statement Starting with the equation for a'', derive an expression for the redshift at which the deceleration of the Universe turned into acceleration. Your expression should contain only fundamental cosmological parameters at the present day such as \OmegaM0 and \Omega\Lambda0...

ok, the universe's expansion is accelerating. I assume the galaxies very far from us are moving apart faster than the galaxies close to us and so the galaxies out there are spaced out much more than our nearby galaxies. However, if one was sitting in one of those far out galaxies, one would...

Can anyone tell me the best way to squirt a jet of water 20 metres. I want it to arrive in a stream not as a mist. Can the jet be electrically charged to hold it together ? Is there a best form of pump ? Can I make a pump that will squirt instantantaneously or will I need a pressurised cylinder...

If standing on Earth and being accelerated by a rocket out in space at g are the same thing, Or at least have the same effects. And if accelerating charges emit light then would an electron sitting on Earth emit light? But I don't see how this is possible because where would the energy come from.

Homework Statement A small weight of mass 'm' hangs from a string in an automobile. Initially, the car is at rest with the weight hanging vertically. Then, the car SUDDENLY accelerates to a rate 'A'. Find the maximum angle \varphi_{max} through which the weight swings by analyzing the motion...

Hi, I'm a bit confused: Picture an elevator accelerating upwards with a person standing inside on top of a balance. Since the elevator is accelerating upwards, the Normal reaction force from the ground must be greater than the weight of the person. My question is: Why doesn't the scale...

In other words why high redshift data is necessary for estimating the acceleration of universe?

OK, I'm not an expert in cosmology but I'm quite curious about it. Current observations tells us that the universe is accelerating (in what sense I don't quite understand). On the other hand, the Friedman equation says that the scale factor a(t) has a positive second time derivative provided the...

You are one light year away from Earth, at rest in Earth's frame of reference. A flash of light is emitted from Earth. You begin to accelerate toward Earth. Does it still take exactly one year for the light to reach you from the time it was emitted?

Hey, I understand why if you watch someone they can never accelerate to the speed of light: their mass approaches infinity so the necessary impulse reaches infinity. But what about in the frame of reference of the person approaching the speed of light. They notice nothing unusual about their...

Homework Statement A pendulum bob of mass m is suspended by massless thread of length l from the ceiling of a boxcar. The car undergoes constant acceleration a along a straight, level track. What, in the small angle approximation, is the oscillatory period tau of the pendulum? Homework...

Homework Statement A car is coming to a top over a distance of 96m Vi = 20m/s r = 25cm find the intial angular velocity, angular acceleration, total revolutions Homework Equations w = v / r angular acceleration = change in w / t d = (Vi + Vf / 2) t The Attempt at a Solution...

Hi I am trying to write a code to find the minimum time until a sphere of expanding light interacts with a set of N particles moving at speed. These particles are acted on by forces which remain constant over the time period. My problem at the moment is that these particles have a mass and...

Homework Statement The Attempt at a Solution Here my figure showing forces: SO here, Tcosθ = mg Tsinθ = mao so tanθ =ao/g = 1/√3 so θ = 30o, right? but it answer says its 60o