Accelerating Definition and 669 Threads

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

Does gravity stop accelerating objects once they are in contact with Earth's surface? If so, why?

Homework Statement A motorcycle is traveling at 1m/s when it is at A (x=0). If the speed is then increased at a=0.1m/s^2, determine the speed and acceleration at the instant t=5s. The curve that its traveling up is y=0.5x^2The Attempt at a Solution I assume that we need to take the...

Homework Statement A 12 kg brick moves along an x axis. Its acceleration as a function of its position is shown in Fig. 7-37. What is the net work performed on the brick by the force causing the acceleration as the brick moves from x = 0 to x = 5.2 m...

A smooth sphere of radius 'R' is made to translate in a straight line with a constant acceleration 'a'. A particle kept on the top of the sphere is released from there at zero velocity with respect to sphere. Find the speed of the particle with respect to the sphere as a function of the angle...

Can something keep on accelerating?if d^2x/dt^2 can be regarded as acceleration, then what is d^3x/dt^3? if not? why not? constant acceleration = circular motion resolves it to be a infinite change of direction, however it does not answer the idea of magnitude.

A cylindrical tin, full of water, is sitting on a platform. What is the maximum acceleration of the platform that will not cause the can to tilt? The dimensions of the tin are known. I'm unsure how to approach the question first off. My reasoning so far has been along the line of this...

This is not a homework problem. It is personal project of mine. Pleases help Say you have a spacecraft that for some advanced propulsion technology is able to accelerate at 1 gee or more indefinitely. This allows the crew walk around as in a gravity and, I think, permit slower than travel...

Homework Statement A man of weight W is in an elevator. The elevator accelerates vertically up at a rate a and at a certain instant has a speed V. The man then climbs a vertical ladder within the elevator at a speed v relative to the elevator. What is the man's rate of expenditure of energy...

Homework Statement Protons are being accelerated through a potential difference of 5,000 V in the gun of a particle accelerator. They must pass between two parallel deflecting plates that are 0.06 m long and 0.02 m apart with a potential difference between them of 1,500 V Homework...

As the universe expands... Is it that we are more on the surface of a balloon, so the expansion is similar for us as it is for our most distant material counterparts? If this is the case than is gravity a consequence of matter resisting time (since the ?big bang or something?) As we...

If the equivalence principle is true then it means that the Earth's gravity field is a constantly accelerating frame of reference. In any accelerating frame of reference the direction of acceleration is always opposite to the direction of attraction. That means that for all observers on the...

Hello, Homework Statement A 45o wedge is pushed along a table with constant acceleration A. A block of mass m slides without friction on the wedge. Find its acceleration in y direction. (Gravity directed down, acceleration due to gravity is g)...

Hi all, Suppose an alpha particle of 3.2 x 10-19 C accelerates from rest between two oppositely charged plates starting from the positive plate. The electric field between the plates is uniform equal to 39000N/C. The distance between the plates is 4.50 x 10-3m Does the alpha particle...

Hi. I'm a sophomore level undergrad trying to understand General Relativity (and all of physics for that matter) with the currently insufficient tools I possess. I was reading Einstein's book, "Relativity", and when I came to the section that describes gravity as the apparent force that arises...

Homework Statement A mass m is resting at equilibrium suspended from a vertical spring of natural length L and spring constant K inside a box. The box begins accelerating upward with acceleration a. How much closer does the equilibrium position of the mass move to the bottom of the box...

Homework Statement The image below shows a mass spectrometer, an analytical instrument used to identify the various molecules in a sample by measuring their charge-to-mass ratio e/m. The sample is ionized, the positive ions are accelerated (starting from rest) through a potential difference...

Homework Statement A 2 kg car travels in a flat circle. At a certain instant the velocity of the car is 24 m/s West and the total acceleration of the car is 9 m/s 2 at 53 degrees North of West. What is its radius? Answer in units of km. Homework Equations F=ma w=(2pi)/T a= w^2...

"accelerating" universe - details and dispute I recently sent an email to several physics professors at CalTech and MIT with a question I have about Cosmology and only one professor (Walter Lewin) replied simply saying good luck! Its not so much of a question as it is a problem. I've talked to...

A lift has mass 800 kg. It is moving upwards and has an accerleration of -0.1 ms-2. The lift is supported by a single cable. What is the tension in the cable? I get T = -7760 N (I'm taking up as negative), just checking what anybody else gets F = ma T + mg = -(-0.1)m T = 800(0.1...

Homework Statement A model car weighs 17N and is accelerated from rest by a 1cm diameter water jet moving at u=75m/s. Neglect all friction, find the velocity of the car after is has moved 1m. Homework Equations Reynold's \sum{\vec{F}}=\int_{CS}{\rho\vec{V}(\vec{V_{rel}}\cdot...

Homework Statement If I spin in circles, in place, am I accelerating? Homework Equations If acceleration is a change in velocity, which is a vector quantity, does only a change in direction count as acceleration? The Attempt at a Solution

Homework Statement Mike is piloting a lear jet traveling at 203.6 m/s over a distance of 2395 meters. How fast will the jet be moving at the end of this acceleration?Homework Equations V = D/T? You need to incorporate one of the "kinematic equations" in order to solve. V=Vo + at X=1/2(Vo -V)T...

Homework Statement A sportscar can accelerate uniformly to 120 mph in 30s. Its maximum breaking rate cannot exceed 0.7g. What is the minimum time required to go 0.5 mi assuming it begins and ends at rest? Homework Equations N/A The Attempt at a Solution Well, first I argued that...

I notice this question has been touched in a general physics thread, but the discussions there on relativistic aspects of the question seemed clearly misleading to me. My questions focus specifically on the view from different frames and the application of the principle of equivalence, so this...

Suppose I have two masses with mass M each connected together by a spring with spring constant k like this: http://img827.imageshack.us/img827/4896/springs1.png Then I apply a force of F at both ends: http://img833.imageshack.us/img833/2562/spring2.png Then using Hooke's law F=kx, the...

1. Homework Statement A mass M1 = 10 kg rests on an incline of angle θ = 60deg. Find the largest M2 such that no accelerations occur. a picture of the problem: http://s861.photobucket.com/albums/ab174/alkaline262/?action=view&current=prob14.jpg 2. Homework Equations f=ma 3. The Attempt at a...

Homework Statement A 2.0 kg block rests on a frictionless wedge that has a 60 deg incline and an acceleration \vec{a} to the right such that the mass remains stationary relative to the wedge. a) Draw the free-body diagram of the block and use it to determine the magnitude of the...

Last night when i was bored, i googled some stuffs about radiation of accelerating charge and saw this http://www.mathpages.com/home/kmath528/kmath528.htm I don't understand the beginning of the article, what does the author mean by "stationary and accelerating" ? or "stationary" ?

First, let me say hello to everyone on the forums! A friend and I have converted a 36" CRT television into a HV source using its flyback transformer. We discharged the tube before taking anything else apart. We have the HV source attached to a thin wire, which causes the air around it to...

Homework Statement Derive the equation that would allow you to calculate the speed of the electrons from the accelerating potential. Homework Equations Fnet=ma Ek=1/2mv^2 Ft=mv The Attempt at a Solution F=mv/t F=ma a=v/t ? I'm not even sure what it means by accelerating...

Homework Statement A train pulls away from a station with a constant acceleration of 0.41 m/s2. A passenger arrives at a point next to the track 6.4 s after the end of the train has passed the very same point. What is the slowest constant speed at which she can run and still catch the train...

I’ve been reading about airfoil lift and have found it rather difficult to find an answer to this question. Is the lift generated by an airfoil primarily dependent on accelerating static air gas particles down?

Hey everybody, I need help on a few word problems. The major problem I'm having is finding a formula to use. A bus is going to a football game and leaves at 4:00pm. It travels 20.91 miles to the game in 33 minutes. What is the bus' average speed in miles per hour? I'm completely clueless...

Since the electrons flowing around a superconducting ring are accelerating they should give off electromagnetic radiation. Based on this, is there any easy way to estimate the half-life of a supercurrent given the radius of the ring? even a back of the envelope order of magnitude kind of thing...

Ok; I'm not a physicist... I'm not a mathematician... I'm not even in school, I'm just a computer guy who watches the Science channel a lot :) So don't yell at me... be gentle :) I've heard and read that the rate of expansion of the Universe may be increasing. Is it possible that it...

I would like to know how to calculate the force of an object that is not accelerating, for example, If I were push on a wall, neither me or the wall would move because the net force would be zero, but how would I calculate the force if I am trying to put on the wall.(I do not want the net force)

Homework Statement A car of mass m has an engine which can deliver power P. What is the minimum time in which the car can be accelerated from rest to a speed v? 2. The attempt at a solution P = W/t (W is work done, t is time) F = ma So, P = Fs/t (F is force, s is distance)...

Are accelerating lines of simultaneity correct?? This is an idea and question that I have been considering for a long time but put on hold while I sought a firmer grasp of the geometry of Minkowski spacetime graphs. My current understanding is this: Lines of simultanieity wrt inertial...

Homework Statement A simple pendulum that consists of a mass m and a massless cord of length L is hanged on the ceiling of an elevator, which is intially at rest. The pendulum is performing a simple harmonic motion. The energy of the mass (Kinetic energy + potential energy with respect to...

Which of the following objects is accelerating: 1. A motorcycle rounds a curve without changing speed. 2. A helicopter ascending straight upward without speeding up for slowing down. 3. A person jogging straight south at a constant speed. 4. A bus starts moving after waiting for a...

Which of the following objects is accelerating: 1. A motorcycle rounds a curve without changing speed. 2. A helicopter ascending straight upward without speeding up for slowing down. 3. A person jogging straight south at a constant speed. 4. A bus starts moving after waiting for a...

Homework Statement A block rests on a wedge inclined at an angle \theta. The coefficient of friction between the block and the plane is \mu.Let the wedge move with horizontal acceleration a to the right. Assuming that tan tan(\theta) < \mu, find the minimum value of a for the block to remain...

Geometrically: Is it correct of think that a line integration in effect converts a curvilinear segment into an equivalent straight line?? If this is basically applicable then it would mean converting the accelerating worldline into a straght line in Minkowski space. My...

Understanding the accelerating/decelerating expansion of universe based on redshift.. I am trying to understand how the expansion of the universe is accelerating, if indeed it is. It's confusing, as some people say that the expansion is accelerating, whereas I have a video lecture where the...