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

learn more… | top users | synonyms

-1
votes
0answers
39 views

Intro Mechanics: Finding ball speeds after collision

So I'm reading about conservation of energy, momentum, balls colliding etc. and unsurprisingly there are hundreds of questions in my textbook where essentially they give me some of the variables (m1, ...
2
votes
5answers
386 views

In an elastic collision, can we choose between cons. of energy and cons. of momentum?

Suppose we have two solid spheres with masses $m$ and $M$, respectively, and that $m$ is significantly less than $M$. The lighter sphere is placed directly on top of the heavier one, and the two are ...
0
votes
2answers
126 views

In a CMCS 2-body system, why does the speed of the particles after collision stay the same?

A particle $m_1$ is traveling with velocity $v$ toward a stationary particle $m_2$. The velocity of the center of mass is given as $v_c=\frac{m_1}{m_1+m_2}v$. Changing to a moving coordinate system, ...
11
votes
3answers
1k views

Can black holes actually merge?

If time stops at the event horizon, can we ever detect two black holes merging? In other words, if you are a short distance away, would you encounter a spherically symmetric gravitational field, or a ...
-2
votes
0answers
52 views

Black-hole meets Black-hole [duplicate]

What will happen if a black hole collides with another black hole of equal mass and diameter and what will be its effect on light?
1
vote
2answers
247 views

Confused about elasticity and collisions

I was solving the following problem and the explanation to it confused me. There are two objects with mass $m$ and $M$, respectively. The object with mass $m$ has a velocity of $\sqrt{2gl}$ and ...
1
vote
3answers
505 views

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: ...
1
vote
3answers
62 views

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 ...
1
vote
3answers
54 views

Force to deflect ball colliding with wall

Suppose I have a ball with a certain coefficient of restitution. The wall can be considered indeformable and with infinite mass. Everything's in 3 dimensions, and the ball can hit the wall at any ...
1
vote
1answer
32 views

Applying impulse to velocity

I'm writing physics engine and so far got some good results but stuck on 1 task i would like to ask. Got some mistake in my formula. Here is a question:Imagine 1 square colliding into another one. ...
0
votes
1answer
39 views

What does the second solution in an elastic collision represent?

A ball of mass 2 collides with a stationary ball of mass 1 elastically! In finding the velocities i end up with two solutions and am not sure how to understand the second solution Simplified ...
1
vote
2answers
44 views

What conditions would allow planetary-sized objects to collide and remain intact?

I am modeling some off-the-wall scenarios to try out with a game engine. One idea is trying to make a planet where some weird catastrophic incident has creates a funny shaped planet. I'm hoping to ...
0
votes
0answers
27 views

Star collision observation

What would these scenarios look like in real world? I mean, what the result would be?: 2 stars (not necessarily same mass) will collide "side by side", like in, they originally were traveling ...
2
votes
2answers
131 views

Factors on which Coefficient of restitution depend

What are the factors on which coefficient of restitution depend? What is the reason for more coefficient of restitution of two glass balls (0.95) than for two lead balls (0.20)?
1
vote
2answers
57 views

Cosmology: collisionless vs collisional fluids?

I try to understand the difference between collisionless and collisional fluids in cosmology. My first question is the following. In the context of FLRW cosmology, we suppose that the Universe can ...
0
votes
1answer
245 views

Transfer of angular momentum during oblique impact with(out) adhesion

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 ...
8
votes
4answers
522 views

Formalism to deal with discontinuous potentials in classical mechanics (hard wall, hard spheres)

It seems to me that Hamiltonian formalism does not suit well for problems involving instantaneous change of momentum, like particle collisions with hard wall or hard sphere gas model. At least I could ...
0
votes
1answer
125 views

Proving the conservation of 4-momentum for a particle collision $A+B\to C+D$

Let me say that particle A hits particle B and two particles come out - C and D; In system S I can write: $$p_A^μ+p_B^μ=p_C^μ+p_D^μ;\tag{1}$$ here $p_N^μ$ is the 4-momentum. Using the Lorentz ...
0
votes
1answer
56 views

Changing linear to angular velocity

Suppose a 1m rod with a hook is travelling at $v$ m/s, and the hook is caught on a hanging line. The rod will change its translational motion into rotation around the hook. Since it is not an ...
4
votes
1answer
138 views

How do I describe and calculate the effect of an impacting object?

My lab studies the physiology of impact injury on biological tissues. I use a pneumatic cylinder to impart injury into a biological sample and then assess the molecular and physiological changes in ...
1
vote
4answers
114 views

How is a ballistic pendulum affected by two objects with different mass?

Imagine that bullet A (made of lead) has twice the mass of bullet B It is shot at the same muzzle velocity as bullet B onto a ballistic pendulum; all other initial variables are the same: size and ...
0
votes
1answer
168 views

Finding the total energy in centre of mass frame

I'm working through a problem in a special relativity textbook (Woodhouse) and I'm having some difficulty. I have to show that if I have a particle of rest mass $M$, total energy $E$ colliding with a ...
2
votes
1answer
624 views

Moment of inertia of rotating particles in center of mass frame?

I am trying to simulate a collision between two molecules. I know the energy for every position/orientation, from which I can calculate the forces. The treatment is classical and the molecules are ...
11
votes
1answer
203 views

Equation derivation for skipping rocks

oWhy can rocks skip over water? For instance, if you conduct an experiment where you drop both rocks from the same height, but give one considerable acceleration in the x direction, one will fall in ...
0
votes
1answer
101 views

Equations for a collision between two particles

Say I have two particles on a 2D plane, they have a x and y coordinate, a x and y velocity, a mass, a coefficient of restitution and a coefficient of friction. What formulae would I need to determine ...
0
votes
1answer
24 views

coulomb collision

I was reading an article by N. Bohr and came upon the following problem (the following wording is actually taken from a book by Thompson - Conduction of Electricity Through Gases): Let $M_1, M_2$ ...
0
votes
1answer
26 views

Comparison of the effects of collisions from an NFL Nose Tackle and a Car with roughly the same momenta

If you get hit an NFL Defensive Tackle who runs at roughly 17mph (7.6m/s) it'd hurt a lot, but if you got hit by a normal car at 1.3mph (about 0.6m/s) it hardly hurts at all, and a collision from an ...
0
votes
0answers
19 views

Can I use the Chi squared test to see if my data fit to the Wigner-Dyson distribution indicating chaotic behaviour? [migrated]

I recently read the paper about Quantum Chaos in Feshbach resonance spectra of ultracold Erbium [1]. The authors analyze their data statistically using the random matrix theory framework for ...
1
vote
1answer
35 views

Particle hitting particles attached with springs [closed]

In classical mechanics if you have a particle moving in two dimensions and it hits a particle at rest although that particle is attached to a spring that is in turn attached to a third particle. ...
2
votes
2answers
47 views

Ideal energy to study higgsstrahlung at a lepton collider

Referring to this diagram: I understand that any energy excess could be taken away as kinetic energy of the final $h$ and $Z$. If you are interested in this (kind of) process should you tune the ...
23
votes
4answers
5k views

What would put a harddisk drive (HDD) under 350G's of force?

I always see the label and it says 350G's withstandable. What would put this over 350G's? Is it even possible to hit 350Gs of force to a hard drive?
0
votes
2answers
47 views

If one object, moving at a constant speed collides with another object - which is at rest - how much force has been applied?

This is one question for which an answer doesn't really make intuitive sense. In elementary school, we learn F=ma, but where's the "a" in a collision such as this? Edit: Plus, there has to be a force ...
1
vote
2answers
185 views

Why isn't jumping against a wall an elastic collision?

According to this calculator http://www.abecedarical.com/javascript/script_collision1d.html when low mass object hits high mass object it is reflected gaining opposite velocity almost the same as ...
0
votes
1answer
92 views

How to calculate impulse force on collision?

I've made a program which is supposed to simulate free fall of a ball on a ground. For collision with the ground I relied on calculating the impulse force with the answer in this Phys.SE question ...
12
votes
3answers
6k views

What happens in electron-electron collisions?

What are the results of high energy electron electron collisions? Are other particles created?
0
votes
1answer
91 views

Newton's law of restitution

Newton's law of restitution. Could someone tell me what the easiest form of this law to use is? I usually try to use e=(v(2)-v(1))/(u(1)-u(2)). Does the law also work if I don't know the direction of ...
1
vote
0answers
88 views

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, ...
15
votes
3answers
2k views

What happens in a car crash?

My mom and I were in a car accident. We are ok, but I want to know how fast the car that hit us was going. We were stopped at a light. The car that hit us from behind was a big GMC SUV. Our car was a ...
1
vote
1answer
59 views

Cube bouncing off a wall

An elastic cube sliding without friction along a horizontal floor hits a vertical wall with one of its faces parallel to the wall. The coefficient of friction between the wall and the cube is ...
1
vote
2answers
14k views

Perfect elastic collision and velocity transfer

So my teacher told me that when you have two identical balls in a perfectly elastic collision, the first ball A will collide with B and afterwards A will stop and B continue. Why is this? Doesn't ...
0
votes
2answers
39 views

Collsion in 2D, find angle and final momentum

Suppose that the collision is completely inelastic. Disregard friction as the surface is smooth. Suppose that one is in the direction of $(1,0)$ and the other $(0,1)$. Is the final momentum the ...
0
votes
0answers
29 views

Can antimatter becomes black hole? [duplicate]

I know it seems unlikely to accumulate sufficient amount of antimatter to let it collapse under its own weight to become a black hole(maybe the gravity works differently I don't know) since they will ...
1
vote
2answers
63 views

Can we create heavier particles with high energy?

It is known that an electron and a positron are created from the energy of gamma ray, is it possible to create heavier particles like proton and neutron from the energy of gamma ray? (if so what is ...
0
votes
0answers
39 views

One extra conservation equation or angle relation for a relativistic collision

Edit: It seems that the derivation for the center of momentum frame was incorrect, due to the fact that the center of momentum velocity changes after the collision. This is also true for the ...
7
votes
4answers
477 views

Aren't all collisions elastic at some level?

The more I think about it, inelastic collisions produce heat and sound which imply motion at some scale, right? Are inelastic collisions macroscopic events that ignore motion at microscopic levels? ...
15
votes
3answers
1k views

Can two spaceships go fast enough to pass straight through each other?

Probability of interaction between two particles tends to wane with increasing energy. Technically, the cross section of most interactions falls off with increasing velocity. $$\sigma(v) \propto ...
6
votes
9answers
21k views

How can momentum but not energy be conserved in an inelastic collision?

In inelastic collisions, kinetic energy changes, so the velocities of the objects also change. So how is momentum conserved in inelastic collisions?
4
votes
3answers
4k views

Why is momentum conserved in an inelastic collision and kinetic energy is not conserved? [duplicate]

We know that in an inelastic collision that total momentum of the system before collision equals the total momentum after collision. But total kinetic energy before collision is not equal to total ...
1
vote
1answer
26 views

Collision and momentum conservation principle

Consider the following problem: A ball is dropped with an angle a between its direction and the normal of the floor and bounces up with an angle b between its direction and the normal of the floor. ...
1
vote
1answer
64 views

After a glancing collision, why do air hockey pucks spins around in circle?

For a lab testing the conservation of momentum, I had to hit an air hockey puck so that it would hit another stationary puck in a glancing collision. After the pucks collided, they travel their ...