What is Bounce: Definition and 124 Discussions

I've been reading on how the distance to the moon is calculated by bouncing a laser signal on the retro-reflectors and measuring the time it takes the light to return to Earth, but what I've seen is that the retro-reflectors do a good job of minimizing scattering by returning the signal along...

I was just thinking about this the other day and wanted to run it by someone.. what do you think about there being a big bounce, and for the universe to unfold exactly the same way, every time for eternity? e.g. I've lived this life infinite times.. and will infinitely more.. Wouldn't any big...

I am writing a QBASIC program that simulates the game of Bagatelle The scattering of He nuclei by gold ions is a famous formative experiment and the ion beam is deflected thru angle theta= 2 times anctan(K/s) But my target (the post) is NOT of zero radius - it is radius R And my ions are...

Homework Statement The questions states, "If you speak while standing in a corner with your face toward the wall, you will sometimes notice that your voice sounds unusually loud. Explain."The Attempt at a Solution Is this because the sound waves are bunched up when they bounce off the corner...

I noticed this on the wikipedia page of the big bounce: " All the so-called fundamental physical constants, including the speed of light in a vacuum, were not so constant during the Big Crunch, especially in the interval stretching 10−43 seconds before and after the point of inflection. "...

Why does a stone bounce off the surface of the water? Why does a bullet bounce off of the surface when it strikes a material at an angle? When I was learning about why glass water bend light, the use of a toy car rolling over different surfaces was used. The slowing down of one side of the...

Homework Statement A marble has been dropped from a given height H + h. There is a metal plate directly below the marble at height h. The marble drops and hits the plate which is at 45 degrees and lands a distance away, R. Find an equation for R(H,h), that is finding the distance the marble...

How heavy does an object have to be so that it won't bounce when dropped from some height h (I'm guessing it's proportional to h as well as other variables)? Is the reaction force from the floor what destabilizes it and causes it to bounce? How does the surface area that comes in contact...

A ball in free-fall (meaning no forces are acting on it other than gravity), upon hitting the ground, will never bounce back up to the spot where it first started to descend. This is due to the Laws of Thermodynamics, which state that, in every action, some energy being used in that action...

Homework Statement Hello! I'm working on my final project for a programming class. Currently I can successfully detect 2D collision between a ball, and a line that can rotate in any direction. However when the ball hits the line I need to change it's velocity so it bounces in the right...

Homework Statement 4. The double-ball bounce Consider 2 balls on top of another that are being dropped from a height h = 2 m, see the Figure below. They will hit the ground and bounce back and we want to compute the velocity of the upper ball after the bounce. (a) (b) We can model this...

Homework Statement I'm supposed to design an "invention" using gas laws, and I've chosen to use Boyle's. But it turns out that a whole bunch of other science is involved, and I just can't handle it all. At it's simplest, this is what the invention is: A giant rubber ball, with a person seated...

These are my equations for the total Universe_mass-energy equivalence based upon the Lambda-CDM model parameters and the Hubble Space Telescope (HST) and WMAP observational parameters and the observable Universe radius in Systeme International units. I attempted to collapse the Lambda-CDM model...

Homework Statement An elastic ball is projected with speed V from a point O of a smooth plane inclined at an angle theta to the horizontal. The initial direction of projection is up the plane, makes an angle theta + phi with horizontal and lies in a vertical plane containing a line of...

Homework Statement So I have been given an algorithm that solves this problem. However, the aim was to make it faster and I have done this. The problem is I fail to explain why it has made the algorithm faster. It's more of a math problem which I haven't understood. I solved this through trail...

Bill Alsept started a thread raising the general question---do cosmic models with regularly repeating big bangs conflict with thermodynamics' 2nd Law? (The law to the effect that, where it can be defined, entropy does not decrease, or does so only by rare accident, at irregular intervals if at...

My textbook tells me that balls don't randomly bounce upward because it is improbable that all of the thermal motion of the particles suddenly align in one direction (upward). But it is just improbable right, or is it impossible? I guess what I'm asking is, is entropy only a statistical...

Can a tennis ball move faster immediately after it strikes the court than immediately before is the question Thoughts ? If you throw the ball up in the air with no forward velocity but significant spin, it will move once it rebounds. Seems to me that that, added to whatever velocity the ball...

How many will argue that heat death is a better end to our universe rather than a bounce into a new universe

In some theories the universe ends/starts with a bounce, is this true with the many universe theory, ie all universes bounce at the same time. this has had me thinking for some time as ,AFAIK there is nothing to say that alternate universes start and end at the same time. In other words some...

When two free neutrons collide at high speed do they ricochet off one another like billiard balls? If so, what is the force that they exert on one another in order to change their velocities? It clearly isn't gravitational or electromagnetic. The only other fundamental forces are the strong...

Ive been working on a new project for my studies but can't seem to get any info on 'switch bounce'

In the picture given to us by loop quantum graivty, the big bang is replaced by the big bounce. So 13.7 billion years our universe bounced from a previous one. In the picture given to us by eternal inflation, our big bang is just a local big bang and there is a far greater inflating sea. If the...

Hey guys, how are you? :D I’m doing an experiment on a squash ball where I drop it from a 0.5m height and work out its "bounced height" to determine energy lose with the table. By per=mgh When dropping it from 0.5 m I get a result of 0.125m on the first bounce. However when I tried it...

Is it from a Black Hole? Is it from a Cyclic Universe?

http://arxiv.org/abs/1010.1258 Big Bounce in Dipole Cosmology Marco Valerio Battisti, Antonino Marciano 5 pages (Submitted on 6 Oct 2010) "We derive the cosmological Big Bounce scenario from the dipole approximation of Loop Quantum Gravity. We show that a non-singular evolution takes place for...

There are hundreds of options with this tool, so this is just an offthewall sample of what you can get: http://graduate-school.phds.org/rankings/astronomy/rank/_M_M____________________________________________________________U I'm not advising anyone to seriously use this, or believe in...

Homework Statement This is not a HW problem. Just refreshing Tx line theory(reflections). I have a pulse of 3.3v, period 36nsecs. (Ton=18ns, Toff=18ns) with a source impedance of 50 ohms, connected to a tx line of impedance 50 ohms. The load is high impedance or infinity. So reflection at...

Homework Statement Basically, an ideal Atwood machine is released from rest (m1 != m2) and I have to find out how high the mass, say m1, bounces after an absolutely inelastic collision with the floor (no energy is lost). Homework Equations Conservation of energy, Newtons equations...

Hi-- I'm doing an end of year project on the physics of trampolines. Anyone who has ever trampolined before knows that you can "double bounce" a person, such that one person bounces right before the other, thus launching the second bouncer higher into the air. In order to do a physics experiment...

I'm trying to understand why tennis balls have a higher bounce on clay courts than on hard courts. I understand that the amount of friction is greater on clay so as to slow the ball's vertical speed down and create a steeper angle of reflection. But I don't see how that explains why the...

I've been trying to understand the big bang theory recently and would appreciate some expert opinions. I was talking to a physicist who is convinced that there was no big bang and that in fact we are living in a 'big bounce' Universe because apparently that is the implications from string...

I have always had problems with Swquences and sum :S A basketball is dropped from a height of 15 m and bounces to 70% of the previous height. The total distance the ball travels when it hits the ground for the ninth time is (give answer to the nearest tenth) i know we probably going to...

I could use some help starting and solving this problem. It is due tonight. Any help would be appreciated. A 190 ball is dropped from a height of 1.8 and bounces on a hard floor. The force on the ball from the floor is shown in the figure (use the link). How high does the ball rebound...

Homework Statement A football (european) that hits ortogonally a surface will reflect such that the kinetic energy of the ball after the collision will be a fraction of the kinetic energy of the ball before the collision. The football makes a free fall from 50 cm to a floor and jumps to the...

1. A man is working in a building when he drops a screwdriver from the top, mass 400 grams, from a height of 40metres. Assuming g = 10N/kg a)If the screwdriver loses 95% of its kinetic energy as heat and sound when it hits the ground, what will be the height of its first bounce? 2...

Why do objects bounce? Let's say you throw a tennis ball at a wall. Why doesn't the ball just transfer its momentum to the wall and then fall on the ground? Does the wall receive more momentum than the ball originally had?

Hello! Since this is my first post I would like to say I am happy that I joined PF and I will try to contribute as much as I can to this great community. So let's get down to the gist of the problem. You are standing 4m from a vertical wall and 0.8m from the ground. You have a bouncy ball that...

I have always had this difficulty with understanding the example of the light-clock: what keeps the light pulse bouncing to and fro between the mid-points of the top and bottom mirrors? Assuming the Earth is inertial for most practical purposes, a coin dropped from a tower hits the ground...

Two objects collide and bounce off each other. Linear momentum A. is conserved only if the environment is frictionless B. definately not conserved C. definately is conserved D. is conserved only if the collusion is elastic A perfectly elastic collision is defined as one in which...

This may have been posted somewhere else but, I would like to know. How do LQG theorists reconcile the fact that the universe is expanding at an accelerating rate, and the LQG prediction of the big bounce. Also I have heard that they say the universe is still expanding because of inertia from...

On earth, if I drop a ball from a building height 100m, what will be the maximum height of the ball after its first bounce? Note: This is not a homework question, I am trying to design a game and I want it to be as accurate as possible.

I've been fascinated by the posts and discussions here about "The Bounce" that seems to be emerging from some LQG models (thanks Marcus and others). I have a couple of questions, which I don't think I've seen in posts here (my apologies if they've been raised and discussed and I've missed it)...

It's been pointed out already at Cosmo forum that a revolution, or at least a minor insurrection, is brewing in cosmology. This paper is part of that. It comes from a different direction compared to some of the other research in nonsingular cosmology. For instance it is not specifically a Loop...

Hey guys, I have a problem that is a decently complex projectile motion. Well, not really, but i can't figure one thing out, which makes the whoel thing a lot harder. I am not sure how to describe this without a picture, but, here goes... an object is at Y height. The object is shot out of a...

Hi, Just a simple question. Does anyone know how a photon interacts with say, a mirror? Does it bounce off the mirror, much like a ball does, or does it get absorbed and then re-emitted? Thanks.

how to cure Switch Bounce? is it a good idea to read the key more than once?

This has always bugged me, and I don't think that I've ever gotten a satisfactory explanation (even though it's a really simple issue): Why do things bounce? The way I see it, you have a ball falling towards the ground. The ground has no momentum, the ball has momentum pointing towards the...

All right, so, we just went over linear momentum in school, and one thing is confusing me: If I throw something at a wall, why does it bounce back? (I'm assuming both the object and the wall are infinitely hard and don't get deformed, and the wall won't move) It seems pretty...

Homework Statement A ball bounces up and down off the ground and each bounce it returns to the same height. Is this simple harmonic motion? Homework Equations None The Attempt at a Solution I don't think it is because in simple harmonic motion the maximun velocity occurs in the middle...