Questions tagged [collision]

Interaction between two or more bodies that results in physical contact and an exchange of momentum between the bodies involved.

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Why is the laboratory frame energy always greater than the center of mass frame energy for collisions? [duplicate]

I looked through lots of sources to answer the question, 'Why is lab frame energy (total energy) always greater than the center of mass frame energy?' Many of them provided lots of mathematical ...
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Why is the laboratory frame energy always greater than the center of mass frame energy?

I have been looking for an answer to 'Why is the laboratory frame energy always greater than the center of mass frame energy during collisions?'. A lot of resources provided mathematical explanations....
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Can you anti-dot? (9-22 from Marion Thorton) [closed]

I'm solving a question out of the textbook and it reduces to the following. a particle of mass 2m with velocity $v_0$ collides with a particle of mass m at rest. The collision is elastic. So using ...
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A rotating solid bar in space [closed]

Say there is a solid bar in space. Imagine it vertically, with the top point labeled $A$, and the bottom point labeled $B$ (these aren't points on the bar, but points in space between which the bar ...
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How is momentum conserved in this example? [duplicate]

Suppose a sticky substance is thrown at wall. The initial momentum of the wall and substance system is only due to velocity of the substance but the final momentum is 0. Why is momentum not conserved?
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How did the Moon get into orbit?

It's the accepted theory that Moon was formed when an object collided with Earth, throwing off a lump of matter which became the Moon. But also, an object cannot be launched into orbit from a planet ...
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Why the rubber ball bounced higher than the glass ball?

For a teaching degree we did the following experiment: Drop a rubber and a glass ball of approx. same size from approx. same height onto laminate flooring. As we expected, the rubber ball bounced ...
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COM frame in Relativistic particle physics

I have a home work: Consider a head-on collision of a 'bullet' of rest mass $M$ with a stationary 'target' of rest mass $m$. Prove that the post-collision γ-factor of the bullet cannot exceed:$$(m^...
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How are particles in a collision chosen?

In synchrotron particle colliders, how are the particles which are collided chosen? For the most part, collisions of different types of particles don't do anything like you might expect in a video ...
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How much water can an object raise after its fall? [duplicate]

Suppose that there is a small object (e.g. hand sized) with volume $V$ and mass $m$ that falls into a water container from a height $h_0$ and with initial velocity $v_0$. Is there a way to compute the ...
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Collision between two non-deformable objects

Let say we have a non-deformable object and we release it into free fall and it hits the non-deformable floor. What would happen? Here is the way I think. Since the floor and the object are both ...
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Is it possible to model elastic collision of two rotating bodies (rotating rods hitting each other)?

If I understand it correctly the laws of conservation linear and angular momentum and kinematic energy isn't enough since these are just three equations and four unknown values. Another thing is there ...
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Is translational/rotational KE conserved when diatomic molecules collide?

When two diatomic molecules of a gas collide, is the collision elastic or inelastic? Is rotational KE also conserved/not conserved? My guess is that translational KE is conserved while rotational KE ...
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Non-acceleration and 0 force

If a mass is moving at the rate of 30/ft. per minute for 5 minutes on a straight line and it strikes a second stationary mass and effects a change of position to this second mass, then we know from F=...
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Force during collision between a body moving with a constant velocity and an accelerating body [closed]

Lets us assume that a train of huge mass is approaching me with a huge constant velocity of the order of hundreds of kilometres per hour. And little me is standing on the tracks but moving with ...
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Momentum and conservation of momentum [closed]

If an object that is moving collides with an object that is at rest and then they both move together what are the momentum and speed changes that take place
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How can four-momentum be conserved in every frame in an elastic collision?

I have this problem: A particle B is standing still while another one, A, is moving towards it with initial 4-momentum $(E,p,0,0)$. Calculate the change in particle A's 4-momentum as viewed from ...
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Smoluchowski theory of Brownian Motion

I am studing Brownian motion, in particular I am reading the book "Brownian Motion, Fluctuation, Dynamics and Application" by Mazo. Now I am dealing with Smoluchowski theory, but I am having some ...
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Why does a billiard ball stop when it hits another billiard ball head on?

(I'm repeating myself a lot here, but it's because I want to make my confusion clear.) If 2 billiard balls are the same exact mass, and one hits another stationary one head on, I have heard that the ...
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Calculate Linear Velocity and Angular Velocity After Collision, in SceneKit [closed]

Here is an attached scheme which i want to write my own custom wall reflection method to simulate the ball collision having right (or left, or top/back) spin. As an example, i have created wall node ...
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How is the rate of decay of a Newton's Cradle affected by the number of spheres in the system?

How does the number of spheres in a Newton's Cradle affect its rate of decay? (assuming only 1 sphere is released initially) From experiment, I observed that the rate of decay of a 5 sphere Newton's ...
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Why is conservation of momentum not valid here?

To explain my confusion, I would provide the following system: The two masses $m$ and $M$, with $M\gg m$, are moving towards each other(as directed by the arrows) with a common constant speed $V_0$. ...
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Matter - antimatter collision [duplicate]

I have read that when matter and antimatter collide they just cancel out each other with the emmision of bright light. But doesn't it violate law of conservation of mass? If the the atoms dissapear ...
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Why does a particle-antiparticle collision produce $2$ photons instead of $1$?

In one of the questions that I did, it asked: What is produced when an electron and positron collides with each other? The answer is $2$ photons. Why doesn't it merge into one? After all, the photon ...
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What are pre collisions and post collisions in forces and momentum?

What are pre collision and post collision exactly? I assume it is before collision and after collision. I can not find an answer on google.
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Kinetic energy vs Quantity of motion

I have to do an impact test for a project that I'm working for. The certified test says that I have to hit with an 25mm ice ball. Instead of that, I have a 250gr metal ball. The ice ball hits at 80 Km/...
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Why can't a faster object increase its velocity during collision with a slower object?

For an example, a car and a truck are linearly colliding against each other,from opposite directions, and the car is faster than the truck.The collision is perfectly elastic. I do not understand why ...
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A question about $y$-axis momentum in an elastic collision involving billiard balls of equal mass

My physics textbook asks me to prove that when a billiard ball moving along the x-axis hits another billiard ball of equal mass in an elastic, non-head on, collision, the two balls will move away from ...
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Force on a crash test dummy during a crumple zone experiment [duplicate]

So in high school physics class, we had to do an experiment where you had a cart with a dummy that went down a ramp (constant height) into a block, where it would stop and you'd measure the distance ...
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If a drop of water hits something at bullet speed, will it damage it?

I can't find this anywhere. If a drop of water hits a glass for example, at the speed of a bullet, will it damage it? Or will it just make the same as a raindrop?
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Rolling ball hits the wall

I play with a small ball in my home. I was experimenting with different ways to hit a ball along the ground and saw a somewhat strange reflection from the wall. If I hit the ball right at the middle (...
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What happens if we directly collide two equally massive black holes at near light speeds? [duplicate]

I am getting intrigued by this question that I don't have the sufficient knowledge to answer it, I've looked up when black holes collide "non-directly" but that doesn't really apply to my question nor ...
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Conservation of energy when dropping a ball [duplicate]

If we drop a bowling ball from one meter above the earth's surface, we are converting its gravitational potential energy to kinetic energy. When it hits the floor, it transfers its kinetic energy to ...
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Why isn't momentum conserved from my reference frame? [duplicate]

Two cars of mass $m_{1}$ and $m_{2}$ collide with each other in a completely inelastic collision. So after the collision they continue to go in same velocity. Now suppose I am in one car. So I will ...
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Bullet hits Earth at speed $0.99c$ [closed]

According to wikipedia, the speed of the neutrino is as close as we can get to the speed of light with an object with rest mass. As per the comments, since neutrinos come in different energies, let's ...
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In which direction would the ball bounce off to?

Given is the following illustration of an arm rotating clockwise centred around the black dot. The top bit of the arm will hit the red ball. In which direction would the ball shoot off to? My ...
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Is it possible to transfer kinetic energy from rigid body 1 to body 2 and conserve total kinetic energy? [duplicate]

This question comes from working with rigid rolling disks and wheels. For example, when a rotating disk comes in contact with a non-rotating disk, the non-rotating disk will start to rotate due to ...
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2answers
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Why do we need to include impulse by string?

There is this paragraph in the solution of the question : Since ball A is suspended by an inextensible string, therefore, just after collision, it can move along horizontal direction only. Hence, a ...
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collision avoiding injury - submerged bodies

This question is actually composed of two separate questions. First part First, let us assume that a heavy object of mass $m$ collides into me while moving at velocity $v$, and I'm standing still. ...
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Violation of the uncertainty principle

Suppose we have two small masses both with the same velocity. Their mass is $m$ and velocity is $v$ and $-v$ respectively. So they collide at some point and the collision is a perfect elastic one. We ...
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Determining the origin of the more dominant sound produced by two colliding bodies

When two objects collide, such as your hands clapping together, how do you determine if the sound being produced is predominantly coming from the physical collision of the two objects, or from the air ...
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Is the total momentum of the ground and a ball that bounces vertically up the ground conserved?

The distance that a ball reaches after it bounce is less than the height from which it was dropped. So $$m_1v_1 + m_2v_2 \neq m_1v_1' + m_2v_2'$$ Where: $m_2$ is mass of earth $v_2$ is initial ...
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Energy transfer through atoms collisions

When a collision between atoms occur like in heat conduction between two gases, does the energy transferred cause an electron to move to a higher energy excitation state, or does it just increase the ...
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Is this a good approximation for the initial velocity of the electron?

I am studying the collision of a very fast proton ($E_p > 100$ MeV) on the electron of a metal (gold to be specific). Is it a good approximation to consider the initial velocity of the electron ...
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Coefficient of restitution for bouncing ball

If I throw a bouncy ball at the ground very hard, it may rebound to a height greater than that from which it was thrown. The coefficient of restitution is given by $$e=\dfrac{\text{speed of ...
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1answer
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Is the “center-of-mass energy” in particle physics related to the center-of-mass frame or not?

For collision of particles the invariant quantity "center-of-mass energy" is defined, as done here. Since it is an invariant quantity it does not depend on the frame of reference chosen. So the name "...
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Bouncing ball with friction

I am trying to write freefem code (same language as c++) for a bouncing ball, but i am not able to notice the result of friction force. At each time the rigid ball hits the rigid ground , the ...
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5answers
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How come I can kick a football further when it's moving towards me?

If a ball is moving towards me, I can kick it further than if I were to kick it if it was stationary. But surely if the ball is moving in the opposite direction, it should take more force to kick it ...
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While throwing a ball up in the air it doesn't hurt but when it comes back at same altitude it hurts why?

While throwing a ball up in the air it doesn't hurt but when it comes back at same altitude it hurts why? Well have the same amount of momentum in both of the cases. Then why does it hurt when it ...
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Can a piece of glass get higher than the height the original cup of glass fell from?

If yes, what physics concepts make this possible? This isn't for any class or anything, is just a honest doubt of mine.

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