# Tagged Questions

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

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### Determine resultant velocity of an elastic particle-particle collision in 3d space

So I have two particles that have collided in 3 dimensional space. I want the particles to rebound off of each other in an elastic manner. How do I determine the resultant velocity vector if I know: ...
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### Calculating a 2D collision between two perfectly circular disks [duplicate]

Assume I have two disks, $p_1$ and $p_2$, of radius $r$, with their own velocities (preferably in $(x,y)$ form, but $(m, \theta)$ works too) and masses (unit-less, but same unit) collide in two ...
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### Explain these graphs of rotation and velocity of pucks on air hockey board

I've been tasked to do a simple experiment on the elasticity of collisions. For this experiment I used two "pucks" (very light circular metal pieces of certain height but hollow) and a table that ...
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### Friction + Bouncing of an Object against an Elastic Wall

I am trying to create the formula for applying a bouncing effect to an element which is already slowing down by friction. At the moment I have an element which moves in one dimension at speed "S" and ...
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### Elastic Collision with objects of the same mass

I understand this is a homework problem. I don't expect anyone to do my homework for me, but help me understand what I am doing wrong. The problem goes: Two shuffleboard disks of equal mass, one ...
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### Where can I find the equations for “quasi” elastic collisions?

Yes, you all talk about neutrinos and spins, but I came out with this basic s**t :D All of us learnt the basic equations of collisions, elastic (everything bounces and energy remains the same), or ...
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### Black Hole Collision [duplicate]

What would happen if two equally massive black holes directly collided at 5% the speed of light. I'm not talking about slowly orbiting each other for thousand of years. I mean one instant catastrophic ...
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### Does inelastic collision mean the colliding particles have to necessarily stick?

In a case when particle 1 is moving vertically upwards and particle 2 if moving horizontally and they collide perfectly inelastically, why would the particles stick ? Since inelastic collision means ...
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### Where does the energy go if a ball hits the ground WITHOUT bouncing? [duplicate]

so if a very un-bouncy object hits the floor and crashes into it rather than bouncing, where does most of the energy go? Does it simply turn into heat from friction? Or does it go into the Earth's ...
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### Help with my bouncy ball lab (I know the factors just not how to approach them) [closed]

In my physics lab we need to determine the factors that account for the energy "loss" during a high bounce ball bounce. I know that energy is "lost" (not really) to heat, air resistance, and sound. ...
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### Relativity collision problem [closed]

Here is the problem: A body of mass m (I assumed this is rest mass, but not 100%), and momentum p(subscript m) collides with a stationary particle of mass M. Find the available energy in the CM ...
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### How can we solve 2D rigid body collision? [duplicate]

I know that usually collision with velocity collinear can be solved by simultaneous equations of both conservation of energy and linear momentum. But my question is when 2D velocity is encountered, we ...
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### How does general relativity explain the impact force after radial inward fall toward Earth?

I understand that, in the context of the Schwarzschild spacetime (General Relativity), a radially inward falling observer follows a time-like geodesic with zero four-acceleration. There are no forces ...
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### Impact on landing with forward motion vs straight down

A skateboarder ollies down a set of stair. Is the impact when landing less than if dropped straight down from the same height?
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### Momentum and Collision of a ball head on? [closed]

I'm stuck on a question with momentum and collision of two balls. Two balls move toward each other. Ball one is moving in the positive direction, has a mass of m1, and a velocity of v initially. ...
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### What is happening from electro-magnetic point of view when a proton and an anti-proton annihilate?

Purely electro-magnetically before a proton (+) and an anti-proton (-) annihilate each other /assume they do/, they form a dipole. What happens after that? In other words, what does an external ...
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### Collision symmetry and measuring the asymmetry in the Drell-Yan process

I saw a talk the other day about an asymmetry in the Drell-Yan process caused by CP-violation: Apparently one way this can be measured (ATLAS is doing this) is to collide protons and observe the ...
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### Car Crash Scenario [closed]

Two vehicles travelling at 80mph in the same direction. Vehicles are directly behind each other. 12 meter distance between them. Front door of car in front rips of and hits the front window of the ...
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### Trajectory of rolling billiard ball after collision with another billiard ball with same mass

So, according to this article http://www.real-world-physics-problems.com/physics-of-billiards.html , the trajectory of white (cue) ball is always perpendicular to the line connecting center of ball ...
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### momentum equation to find velocity of solid particle after collision [closed]

If a particle collides with a liquid drop, particle might penetrate into drop and so the velocity of particle reduces. i.e. a sudden change in particle velocity happens right at the collision moment, ...
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### Inelastic Collision and Energy

How is is possible for momentum to be conserved and for KE to not be conserved? Momentum is related to velocity and velocity is related to KE, therefore if KE was lost, how can the system have the ...
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### How to explain the momentum exchange of two solid particles collision at molecular scale?

Here is my question: assume two solid sphere collided to each other in vacuum, at macroscopic, it can be explain by Newton's law. But at molecular scale, does the surface atoms touch to each other or ...
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### Relating to Inelastic Collisions

There is a very simple equation for an inelastic collision but it really only applies to 2d scenarios: $$v = \frac{(m_1 u_1 + m_2 u_2)}{(m_1+m_2)}$$ What would be the equation for an inelastic ...
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### A particle collides with another particle in an (infinitesimally long?) elastic collision, what is the resultant force?

When an object collides with another object in an elastic collision, the first object exerts a force on the second object (and vice versa); how do you calculate the force that the object experiences? ...
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### Throwing a baseball against the back of a car [closed]

We, some fellow students and I, are trying to figure out what to. But we simply do not know which formula to use at question a. We found the following: $\Delta P=(2mv_{ball,i}M)/(m+M)$ Could someone ...
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### Work-Energy theorem vs conservation of mechanical energy? [closed]

Bodies A and B are moving in the same direction in a straight line with constant velocities on a frictionless surface. the mass and the velocity of A are: 2kg and 10m/s. The mass and the velocity ...
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### Modeling a collision phenomenon [closed]

I have a single water droplet (d~3 mm) which collides with a solid particle (d~2 mm) with a relative velocity around 10 m/s. After collision, particle rips the droplet and goes through it. Therefore, ...
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### Elastic Collision [closed]

A cube has a side length of 20 cm. An atom in the gas moves around the cube as shown. It continually bounces off the four lateral walls of the cube. The atom has a mass of 6.6×10−27 kg. Because of the ...
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### Books on collision probability and collision processes

Are there any books specifically on collision processes between atoms and molecules and collision probability? I would like to get an overview of the factors that determine collision probability ...
332 views

### Transfer of angular momentum during oblique impact with(out) adhesion [duplicate]

I am solving a problem of 2 identical spherical particles colliding. The impact is oblique. I consider both normal and tangential contact forces. Tangential force is a combination of elastic force ...
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### Collision Resolution System Adding Velocity Into System

In my 2-dimensional physics simulation, I have a rectangular rigid body 'a' with infinite mass (the floor), and a rectangular rigid body 'b' with finite mass above it turned at a slight angle. When ...
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### Throwing ball against oily/slippery wall

I would like to know whether a ball bounces back normally if you throw it against an oily wall. Like a wall watered down with oil. Basically I want to know if it will actually slip before bouncing ...
148 views

### Bullet entering target [duplicate]

I've been given this question: A bullet entering a target with an initial velocity of $u$ loses $\frac {u}{n}$ of its velocity after penetrating a distance $a$ into the target; how much ...
131 views

### 2d pool collision with rotational motion

I'm trying to calculate two 2d disks' collision with rotational motion. The collision is perfectly elastic: the sum of translational and rotational energy is conserved. In the instant of the collision ...
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### Which body position causes the least amount of negative acceleration? [closed]

Let's say you are in the air 500 meters above flat land and you have no parachute. Which pose - forming a sphere or spreading all extremities to make yourself as wide as possible or other - is the ...
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### Electron and photon collision

So electron moving left ($v_{initial}=0.8c$) collides into photon going right. After the collision electron is moving to right ($v_{after}=0.6c$) and the photon is moving to left. What is the ...
158 views

### Asteroid collision debris calculation

I wonder how to determine the directions, in which the collision debris is launched when 2 asteroids collide. I am aware of: m1*v1 + m2*v2 = m*v = m3*v3 + m4*v4 + m5*v5 + ... and this works just fine ...
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### Nucleon-nucleon collision density

Can someone help me derive expression for nucleon-nucleon collision density as a function of transverse plane coordinates (ultra-relativistic heavy ion collisions) using Wood-Saxon nuclear densities( ...
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### Decrease in Intensity [closed]

A beam of particles pass through a target made of thin foil of a very small thickness $\Delta x$ having $N$ particles per unit volume. Let the collision cross section be $\sigma$ . If the intensity of ...
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### Calculating Impact Velocity Given Displacement and Acceleration

Assume a car has hit a wall in a right angled collision and the front bumper has been displaced 9 cm. The resulting impact is 25g. Also, it is evident by skid marks that the car braked for 5m with ...
761 views

### Can I throw a stone through my window without breaking the glass?

As far as I know, most of an atom is vacuum. Therefore, in theory, would it be possible for me to throw a tiny stone through my window without breaking it because no matter actually collides?
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### How can the bodies attain same velocities during the max. deformation during collision?

My book writes: Collision between two bodies is almost similar to the case where there is a spring between the two colliding bodies. At the instant they come into contact , the rear ball has a ...
577 views

### Can a photon survive a collision? If so, is it at rest during the process?

Background Irving Kaplan, in Article 6.7: The Compton Effect of Nuclear Physics (2nd Ed.) explains the Compton effect as follows: Compton (1923) was able to show that when a beam of ...
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### How can counting the number of cracks in glass tell you about the speed of impact? [closed]

A recent article, Counting cracks in glass gives speed of projectile (Andrew Grant, Science News, May 1 2013) indicates that the number of cracks in a broken glass can tell you information about the ...