Accelerating Definition and 669 Threads

if the uverse is expanding and known to be accelerating, at what rate is this acceleration? even at small # over the billions of years, would it not be at speed of light already, and if so, how would observable mass be traveling at the speed of light?

In classical physics, when electric charges accelerate, they are expected to radiate. Electromagnetic waves, are by their nature the result of changing electric and magnetic fields. But is it possible to have acceleration of charges without having changing electric and magnetic fields? One...

So in my physics class this last semester, we learned about normal force, weight and centripetal acceleration and all that good stuff. So i got to thinking about a ball on a string being spun around my head and i got to thinking about the force diagram you would draw for that, and obviously you...

The electron created and emitted in the beta decay of a proton has an initial velocity close to the speed of light. When I try to calculate, not taking into account relativity, the force needed to accelerate an electron to that velocity over a distance the size of a proton, I get about 45 N...

After looking at the "doppler effect" explanation of the twin paradox, I'm under the impression that the difference in the age of the two twins has to do with the part of the diagram where one of the twins is accelerating. But, my question is, what about the "coasting" part of the diagram? So...

1. Homework Statement A mass of 1 kg hangs inside a boxcar of a train. If the train accelerates at 7 m/s^2, what is the approximate tension in the rope? A: 12 N Homework Equations F=ma The Attempt at a Solution I originally thought of doing this problem as pythagorean theorem, but I wanted...

I can understand that a free falling frame in a curved space with a non-zero Riemann tensor has a zero Ricci tensor but I have a doubt about the opposite; does an accelerating frame in a vacuum space have a non-zero Ricci or Riemann tensor? if so, where do components of energy momentum tensor...

I was wondering if it is possible to setup a Tokamak like chamber with some sort of varying magnetic field arrangement around it, that can accelerate deuterons or other light nuclei, as if those nuclei were 'pulled' by a constant electric field of between 1kV and 100 kV (n.b. this should not...

Homework Statement [/B] In Minkowski spacetime we are considering a (series of) frame(s), S', attached to a rocket with constant proper acceleration. The rocket's speed in S is v. We find with boundary conditions x = 0 at t = t' = 0 the relationships between S and S' (for x' = 0, i.e. at the...

Homework Statement Rocket is accelerating constantly. Let S' be instantaneous rest frame of rocket and S be frame in which rocket is observed moving at velocity v. Homework Equations Given: $$ dv = dv' (1 - v^2) $$ Must prove: $$ \frac{dv}{dt} = \frac{dv'}{dt'} (1 -...

Assume that a motorcycle of mass m has two wheels that are equidistant from its centre i.e the force on each wheel is m*g/2. If the motorcycle accelerates forward, will the two forces on each wheel (measured instantaneously) remain the same? If not, how can one mathematically describe the...

A block of mass m rests on a frictionless wedge that has an inclination of θ and mass M. Find the acceleration of the wedge M to the right such that the block m remains stationary relative to the wedge 1. Homework Statement a, \theta , M, mHomework EquationsThe Attempt at a Solution Draw a...

I don`t understand how synchronization of clocks can be made in an accelerating frame. let`s put a source of light at the center of an accelerating rocket. From it, many pairs of pulses are emitted one at a time in two opposite directions. Because the source is located at an equidistant from two...

Physicists have observed the cosmic radiation background to conclude that the universe is flat (or within the margin of error of being flat). This means that the Universe contains the critical density needed to keep it flat, which is a mix of ordinary matter, dark matter and dark energy (I...

T1. Homework Statement a wooden ball of mass m is kept inside water by the help of a massless string shown in the figure. One end of the string is fixed at the bottom of the vessel. when the vessel containing the water is accelerated upwards with acceleration a , will the tension increase and...

Homework Statement Homework Equations a= (m2g)/(m1+m2) The Attempt at a Solution Which is option 4. But the answer doesn't match

This may be a basic question but why does light ray bend in accelerating elevator but not in one with constant velocity. I know a frame of reference with constant velocity is indistinguishable from a stationary one from the inside but I feel like like somehow the light seems to know whether it's...

The farther out we look, the faster the galaxies are moving away from us. Closer galaxies are moving away from us, but not as quickly. We reason that when they're as far away as the more distant ones, they'll be going that fast, too. So we infer that the universe's expansion is accelerating...

Homework Statement why the vertical rise of the surface is given by the formula as shown in the notes ? shouldn't it = Δs = (g +az ) Δx / ax ? Homework EquationsThe Attempt at a Solution

Does an accelerating charge, such as one turning a corner emit an em wave or just a pulse? Classical logic dictates it should just be a pulse as there is no oscillation. But which is it?

This other thread got me reading about metric expansion and this graph: https://en.wikipedia.org/wiki/Metric_expansion_of_space#/media/File:Universe.svg I am possibly misreading the graph, but it seems to suggest that, if we are in an expanding universe (large dotted line), and curvature is...

I have attached a picture so that it is easier to visualize this problem. The information is all in it. The number scribbles are just my attempts to solve it: http://i65.tinypic.com/2qlbn9h.jpg The current topic we are on in class is Newton's Laws and we have covered moments and equilibrium...

Hello. I am having some trouble to understand conceptually the behaviour of such a system: So, both blocks are in contact with the floor, one has mass M and the other has mass m. Then we apply an upwards force F on the axel of the pulley. How does the system behave? My initial thought is...

Hello, My question is about accelerating charges generating electromagnetic radiation, and is more of a theoretical one, or a thought-experiment in my head...probably because I'm not totally understanding something. I was playing with this applet which simulates the electric field lines of a...

In an inertial frame of reference let numerous standard rockets that load synchronized standard clocks place on all the space lattice. Simultaneously the rockets start to move with same intrinsic acceleration to the same direction. In other words there exists a common instantaneous inertial...

Homework Statement two objects are at rest in an inertial reference frame. Two objects accelerate simultaneously in the same direction until reaching half the velocity of light and then halt simultaneously. The two objects are initially connected by a thread just long enough to cover the...

Homework Statement source:http://www.wired.com/2014/07/a-rolling-object-accelerating-down-an-incline/ For a ball rolling on an incline, I know how to calculate the acceleration. However, I am quite confused about a situation. What if static friction acting on the ball is equal to the...

Homework Statement [/B] Consider a half-atwood machine on a cart as below, with mass m_2 attached to M via a frictionless track that keeps it pinned to M but allows it to move vertically. All surfaces (except between the wheels/ground) are frictionless, and the pulley and rope are massless. If...

Homework Statement AP French Mechanics Problem 7-1 Two identical gliders, each of mass m, are being towed through the air in tandem. Initially they are traveling at a constant speed and the tension in the tow rope A is T(sub0). The tow plane then begins to accelerate with an acceleration A...

Let's say I'm floating in space in a spaceship, and there are some stars around. Now I turn on powerful spaceship engines. This causes a huge acceleration, which causes the brightness of some stars to increase a lot. (Those stars that are up in the pseudo gravity well become bright) Does tidal...

Homework Statement Two wooden crates rest on top of one another. The smaller top crate has a mass of m1 = 20 kg and the larger bottom crate has a mass of m2 = 80 kg. There is NO friction between the crate and the floor, but the coefficient of static friction between the two crates is μs = 0.79...

How are we, and the universe effected from its accelerating expansion? Also how will our perception of the world around us be effected, since the universe is expanding and light is constant? <-Will things appear to move slower? I know that we only experience just a small fraction since the...

Homework Statement When a ball is bounced from the ground, the Earth exerts the force necessary to reverse its velocity. Is there a simultaneous force exerted on the earth? If there is one, why don't we perceive any acceleration of the earth? Homework Equations Newton's second law: net F=ma, F...

Homework Statement A ball bearing rests on a ramp fixed to the top of a car which is accelerating horizontally. The position of the ball bearing relative to the ramp is used as a measure of the acceleration of the car. Show that if the acceleration is to be proportional to the horizontal...

Hey guys, what do you think about this: Let's put a planet in empty space, on the surface of the planet we put a a guy named Bob, Bob's task is to accelerate the planet by pulling on a provided rope. He must extend his arm, grab the rope and bend his arm at maximum force. Bob's identical twin...

Homework Statement The velocity of a conveyor is V=30+0.1t2. a box of mass m=3[kg] falls from zero height at t=0. the kinetic coefficient of friction is μk=0.4 and the static is μs=0.5. 1) At which times the friction is kinetic and at which static 2) What's the box's velocity in the different...

The Universe is constantly expanding, and from the observation of Hubble, super novas, the figure turns out to be a acceleration. The theory that's most accepted seems to be dark energy at work. As the story goes, before big bang, there was nothing, maybe not even time or space, so how does...

Homework Statement All surfaces are smooth. mass m1 is attached to m3 with a smooth rail, it can't detach. What are the accelerations of the masses relative to the floor. Homework Equations Conservation of momentum: ##m_1v_1+m_2v_2=0## The Attempt at a Solution a3 and a2are the acceleration...

Can we really say that the universe is accelerating its expansion because we find that galaxies further away have more redshift? We know that we are looking back in time when we look at the stars, and when we look at the galaxies furthest away from us, we are seeing them as they were a long time...

Homework Statement I have the following situation: car 1 is distance di ahead of car 2. Car 1 has either a constant speed v1 or accelerates with a1 (I eventually want to cover both cases). Car 2 accelerates faster than car 1. Car 2 is eventually going to catch up with car 1. I want to calculate...

Homework Statement Mass m lays on the smooth triangle of mass M. what is the acceleration of M so that m will stay in place. Homework Equations Newton's second law: ##F=ma## The Attempt at a Solution $$\tan\alpha=\frac{ma}{mg}\;\rightarrow\; a=g\tan\alpha$$

Homework Statement Show that Newton's Second Law is NOT valid in a reference frame moving past the laboratory frame of problem 1 with a constant acceleration? Problem 1: In a laboratory frame of reference, an observer notes that Newton's Second Law is valid. Show that it is also valid for an...

I am writing this thread because I have too often had to explain this and I basically wanted to have a resource available to direct folks to, and, frankly, the Wikipedia topics on this are pretty vague on the explanation. Any questions, comments, or corrections are greatly appreciated. So, here...

Hello, I would need some guidance to calculate the force required to accelerate a vehicle up to a certain speed over given amount of time. This might seem simple but I am not sure if I am on the right track anymore. I did some online searching and I couldn't really understand it. 1. Homework...

Referring to the problem in the attachment, the author mentions that if we consider the coordinate system attached to the bicycle and the bicycle accelerates or decelerates, the flow past the bicycle becomes unsteady. For an unsteady flow, we know that nothing changes at a given location on a...

From the equation F = ma, is force an accelerating mass? So if an object is traveling at constant speed it doesn't have a force attacking on it? How about a car traveling at constant speed? A force will need to be applied to it otherwise the friction would stop it right? But it wouldn't...

Sorry for the lame question, but I was wondering if someone could help answer the following. I have two synchronised clocks which I place on two different space ships which then accelerate away from me at the same rate and time until they reach a given speed. Ship A then slows down to be at...

Okay so I have a problem with what my textbook is saying. It defined pair production as a process in which a photon of electromagnetic energy is converted to a pair of particles. But then it gave the discovery of an antiproton. Which was when a proton was accelerated to 6MeV and collided into...

Hi i have a question, i m a engineer but i have probably a dumb question ¿if the Expansion of the Universe is accelerating, but exist a speed limit "c" this tell me that at one point the universe will expand at a constant rate?

If I run a current through a wire with a 90 degree turn, what prevents the electrons from continuing out of the wire is a straight forward path? What force accelerates them in the direction of the wire?