Accelerating Definition and 654 Threads

http://arxiv.org/abs/0803.0982 Dark Energy and the Accelerating Universe Joshua Frieman (Chicago/Fermilab), Michael Turner (Chicago), Dragan Huterer (Michigan) Invited review for Annual Reviews of Astronomy and Astrophysics; 53 pages, 18 figures (Submitted on 7 Mar 2008) "The discovery...

Consider three clocks A,B and C all set at t=0 at t=0 Clock A is stationary on earth Clock B is on a rocket at a distance of 16.43 (10^14) meters away from Earth and accelerates instantaneously to .6c and arrives at earth. Clock A time = 105.6 days. Clock C is on a rocket at a...

Homework Statement The coefficient of static friction between a truck and road surface is \mu_{s}. What is the maximum acceleration of a four-wheel-drive truck of mass M if the road surface is at an angle of \theta with the horozontal when the truck is... a). Climbing b). Decending...

[SOLVED] Simple pendulum: does the period change in a horizontally accelerating frame Homework Statement Simple pendulum which is 5.0m long. What is its period when it is in a truck accelerating horizontally at 5.0m/s/s? Homework Equations w = sqrt(g/d) w = 2pi/T The Attempt at a...

I'm considering doing a sci-fi comic or novel in an Einsteinian universe, no wormholes or faster-than-light travel. I haven't seen this done very often. It's been a while since I've worked with math, though, so I'm having some trouble. First, I just want you to check my math. The relativistic...

Homework Statement A 45 degree wedge is pushed along a table with constant acceleration A. A block of mass m slides without friction on the wedge. Find its acceleration (gravity is downwards),Homework Equations The Attempt at a Solution I answered the above question on another forum, but got...

I need to graph a distance vs. time problem. I have a car uniformly accelerating from rest to 10 seconds. Would it be a normal dianagnol line, or would it be a power curve? help is welcome.

[SOLVED] Fictitious force and accelerating airplane Homework Statement The question asks me to draw a free body diagram for a person standing in an accelerating airplane, and to indicate the fictitious force and any real forces acting on them. The airplane accelerates at 2.22 m/s^2...

Suppose we have two equal masses, say at least the mass of our sun separated by a distance of 1 ly and devoid of all outside forces. These objects would keep accelerating towards each other until they approach the speed of light and as their mass increases their acceleration decreases but...

My textbook says the following: "If the center of mass of the system is not accelerating relative to an inertial frame, that origin can be any point. However, if the center of mass of the system is accelerating, the origin can be only at that center of mass. As an example, consider a wheel as...

A 165-lb person is standing on a scale in an elevator. What is the reading on the scale in Newtons if the elevator is ? a) accerlating upward at 2.0m/s? b) accerlating downward at 2.0m/s ? a= 11.8 m/s *(165*0.454)= 884N b= 7.8m/s *(165*.454)= 584N

Homework Statement A car accelerates at 1 m/s^2 up a ramp which makes an angle of 5 degrees with the horizontal. Ignoring friction and air resistance what fraction of the power the engine puts into the car's motion goes into the car's kinetic energy? Homework Equations The Attempt...

Homework Statement "During the launch, a rocket is accelerated with 20.0m/s^2 upward. A 105.0kg astronaut is more concerned about his weight than about his safety and is standing on a scale. What is the scale reading in kg?" Homework Equations F=ma and also 4.45N=1lb The Attempt...

Homework Statement Imagine being on an airplane in flight. You have a cup of tea on a table in front of you. The plane then starts to accelerate at the same altitude it had initially. The coefficient of static friction between the cup and the table is 0.250. What is the maximum acceleration...

Expanding and accelerating space in layman’s terms. First, Einstein: You and I buy two really nice watches. They are accurate to within a billionth of a second per year, and will calculate to the trillionth of a second. You and I are standing next to each other as we synchronize our new...

If big bang theory is true, what could cause the expansion of the universe to actually speed up AFTER the explosion? Wouldn't there have to be some "force" from OUTSIDE the universe for the expansion to speed up after initial conditions were set in motion? It is still considered true that...

Distance traveled by an accelerating truck with a steel load. With a twist! Homework Statement Consider a large truck carrying a heavy load such as steel beams. A significant hazard for the driver is that the load may slide forward crushing the cab, if the truck stops suddenly in an...

Hello, this is my first post here. I hope you can answer my current question, and that i will be able to answer other's questions later on! I have all the footwork (equations) under control, but I can't figure out how the forces are divided in this situation: There is a force applied...

A bucket of water with mass 6.00 is accelerated upward by a cord of negligible mass whose breaking strength is 66.0 .

A runner accelerates to a velocity of 4.15 m/s due west in 1.5 s.His average acceleration is 0.640 m/s also directed to the west . What was his velocity when he began accelerating ?

Homework Statement A 20.0 kg packing case is initially at rest on the floor of a 1400-kg pickup truck. The coefficient of static friction between the case and the truck floor is 0.30, and the coefficient of kinetic friction is 0.20. Before each acceleration given below, the truck is traveling...

I understand that in form of vectors but conceptually speaking, I don't get it. Btw, why do accelerating charges emit energy?

If we have an object that is theoretically set to accelerate constantly for an unknown amount of time (disregarding the issues that alone brings up), what formula would be used to calculate its velocity? I know we can determine final velocity for after t amount of time, but would...

I’d be grateful if someone could shed some light on how we know the expansion of the universe is accelerating by the luminosity of supernova types 1a? I'm currently reading 'The Extravagant Universe' by Robert Kirshner and he talks extensively about searching for supernova. While this is done in...

Homework Statement Assuming equal masses, how would the detection times of 3H+ and 3He+ compare [as they're both accelerated toward a detector in the direction of a constant E field]? A) 3H+ would have a longer flight time than 3He+. B) 3H+ would have a shorter flight time than...

Let (t,x) be coordinates of some point P in some inertial frame O. Suppose that at (0,0) there is a particle that has velocity u and acceleration a in the frame O. If the origo of a frame O' is attached to this particle, then what are coordinates (t',x') of the point P in the frame O'? Or does...

It is often stated that ANY accelerating charge radiates, so this includes uniformly accelerating charges. But the radiation reaction force is proportional to the THIRD derivative of x, so it vanishes when acceleration is constant. What's the deal here? Here's a graph which supposedly shows...

Hello, I have a question for homework. The question reads: A body of mass m=4.8 kg is standing on a ramp inclined in an angle of α=12 degrees. The static friction coeficient between the ramp and the body is μ=0.24. The ramp, which is inclined to the left, is in a train, which accelerates to...

We know through observations of distant SN that the deceleration parameter is negative and this implies that the universe is accelerating. This is just me but when I think about acceleration, I think of a vector quantity with units of m/s^2 and has magnitude and direction. do we know the...

This site: http://curious.astro.cornell.edu/question.php?number=575 , states that "Astronomers now have strong evidence that we live in an "accelerating universe" how is that possible, where does the repulsion force come from?

I'm a physics grad student attempting to do a research paper on the social implications of the accelerating universe. To do this, I'm trying to find information on theories for and against the accelerating universe from before the supernova observations by the Perlmutter and Riess teams (which...

Homework Statement An electron is accelerated from rest through a potential difference of V volts. What is the final velocity? I did: qV=\frac{mc^2}{\sqrt{1-\frac{v_f^2}{c^2}}} And solve for v, but I get an unreal answer. What am I doing wrong?! Homework Equations The Attempt at a Solution

Problem. A simple pendulum oscillates with frequency f. What is the frequency if it accelerates at 1/2 g (a) upward, and (b) downward? Let m be the mass of the bob at the end of the cord of length l that is making an angle \theta with the line through the point of equilibrium. Given (a), the...

How does a charged particle, that is accelerating or de-accelerating, produce an EB wave? What is actualy happening when an EB wave is produced? The EB wave has energy, what is happening to the energy of the charged particle? Is the charged particle slowing down, if so why is an EB wave...

Hey ,if we need to calculate time dilation with an accelerating frame of reference,cant we simply use the lorentz trasnformations and use instataneous velocity in place of relative velocity? Alsousing einsteins derivation of the lorentz transformations we get 2ct=0 Now how do we explain this?

Does speed of light Change with respect to accelerating frames It shouldn't be as gravitational time dilation exists

hi... a rocket of mass M is flying through a dust cloud the cloud has a density of P. the rocket's cross section is A. every dusticle the rocket colides with becomes permenantly attached. the rocket is ejecting material (as a propellant) at the same rate that it assimilates it. the speed of...

I wish to accelarete out into space at 9.8m/s/s for 1 day. The reason I want to accelerate at 9.8m/s/s is because I want to feel the normal effects of gravity as I travel. After accelerateing for one day, I want to look out my rocket window, and take a snap shot of our sun, then I want to...

Homework Statement Why is helium balloon in accelerating car tilting forward? Homework Equations The example that I think that I understand - is simple pendulum in accelerating car - and everything there is clear - g(effective)=g-A (all of them are vectors). The Attempt at a Solution So...

I have a question for homework, and this is a high school physics class. The question reads: Suppose that you are standing on a train accelerating at 2.0m/s^2. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide? I've drawn a free...

"As your jet plane speeds down the runway on take off, you measure its acceleration by suspending your yo-yo as a simple pendulum and noting that when the bob (mass 40g) is at rest relative to you, the string (length 70cm) makes an angle of 22 degrees with the vertical. Find the period T for...

We start with a non accelerating long rocket having a clock C1 and photon source S at the front and a mirror M at the rear - photons are emitted at timed intervals recorded on C1 and their return is measured by C1 - so the round trip time for the rest frame is established. The rocket is then...

I seem to be specializing in plumb bobs this week:rolleyes: A box car has a freely hangling plumb bob (from the ceiling). It is accelerating up an incline. which makes an angle b with the horizontal. The plumb bob makes an angle c with the perpendicular to the ceiling. Find the acceleration...

a boat moves through the water with 2 forces acting on it. one is a 2021N forward push by the motor on the propeller, and the other is an 1774N resistive force due to the water around the bow. What is the acceleration of the 1146kg boat? Answer in units of m/s^2. would i use a=f/m for this...

This seems like an easy problem but my answer is incorrect. Imagine a boxcar traveling up a 9.85 degree slope with constant acceleration a. In the boxcar is a pendulum that hangs 24.05 degree from the perpendicular to the boxcar's ceiling and floor. Find the acceleration. It seems to me that...

I'm pretty sure this is an easy problem but I don't know what formula to use - At the local grocery store, you push a 16.2 kg shopping cart. You stop for a moment to add a bag of dog food to your cart. With a force of 12.0 N, you now accelerate the cart from rest through a distance of 2.02 m...

Two blocks are fastened to the ceiling of an elevator. The elevator accelerates upward at 1.70 m/s2. The blocks both have a mass of 11.5 kg. Find the tension in each rope. ______________________ ....| ....| ....| ...__________ ...|...| ...|...| ....| ....| ....| ...__________...

energy and mass both exert gravitational force right? so the question "will a very fast object become a black hole" isn't answered by saying that the rest mass doesn't change right? I remember asking this question before and being told that it wouldn't since the rest mass stays the same when...

A car starts from rest and accelerates uniformly for 6s. The distance traveled in the 6s is greater than the distance traveled in the 1st second by a factor of what? how would i go about doing this?

I have heard that people say the universe is accelerating, however i cannot find direct evidence of these claims anywhere. What has led people to believe that the expansion of the universe is accelerating?