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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How does conservation of momentum work here? [closed]

Imagine 2 oppositely charged particles attracted to each other, say an electron and a nucleus, assume their force of attraction is very large compared with any external applied force we're about to ...
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270 views

Relativistic collisions (elastic) - stationary target, equal mass [closed]

A moving electron with energy $E$ hits a stationary electron. Question is to find the scattering angle (the angle between the paths of the two electrons after collision) in terms of the energy $E$ and ...
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Mechanics of a stationary grain resting on the surface of a granular bed which is subject to a collision

Consider the following stationary configuration of three disks (in 2d): I would like to consider the two supporting (lower) disks as entirely static, but the upper disk can move, and it only rests in ...
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66 views

Elastic collision between a circle and a point [duplicate]

In a 2D environment, I have a circle with velocity v, a stationary point (infinite mass), and I am trying to calculate the velocity of the circle after a perfectly elastic collision with the point. ...
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Restriction for the rule: change in momentum=force x time?

I did a prac about impulse and momentum. F∆t=m∆v indicates that the change in momentum should same as the area under force time graph. I ran a experiment where a cart is released on a slope and hit ...
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38 views

Calculating velocities of 2 squares after collision

If I have 2 squares each with random velocities, and both with the same mass, would it be possible to calculate their velocities after a collision, and how would I do so?
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65 views

Which formula for elastic collision?

When researching a bit about elastic collisions, I've been confused about how many different ways there are to do this. I've seen multiple methods, some of which are extremely complex (using sine and ...
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What work is done by the wall when a ball hits it?

So, in my physics textbook it's written that the kinetic energy possessed by a body is equal to the amount of work done by an opposing force to stop the body, now that got me thinking that when a ball ...
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1answer
105 views

Which is more important for a force of the impact mass or velocity? [duplicate]

If a 2 times bigger mass collides with an object in which a 2 times smaller mass collides but with 2 times the speed which one will produce more force on the object? The object is stationary before ...
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Impulse imparted during elastic collision [closed]

Lets say there are two objects a of 1kg and a very heavy block. The light mass has a velocity of $12$ $ ms^{-1}$ towards right. The heavy block has a velocity of $10$ $ ms^{-1}$ towards right. The ...
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Inertia of a falling weight

I use a standard device (penetrometer) that uses a 10 kg weight that is dropped a constant distance to cause a probe to penetrate soil. The penetration distance after 4 blows is recorded. If I were to ...
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Why do objects rebound after hitting the ground? [duplicate]

When an object, say a shoe, falls from a height (under the influence of gravity), it rebounds after hitting the ground. For an object to move upwards, it requires a force to overcome its weight. When ...
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1answer
86 views

Mathematical expression of impulsive forces during a collision

I'm facing with problem regarding collision between bodies. Specifically, I need to understand the impulsive forces that arises during a collision. Sometime ago, I posted two questions (this and this) ...
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Falling from a high cliff [closed]

I've always wondered about the reason why falling from a high cliff could actually cause death, is it the normal force exerted back from the ground? or is it related to energy? or what? thnx.
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Predicting elastic collisions [closed]

I want to predict how a collision will go with physics. Say I have a perfectly elastic 1-dimensional system with a frictionless ground and two objects of masses say $m_1$ and $m_2$ moving with ...
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1answer
55 views

“Plushness” of a simple mechanical damper?

What heuristics generally define the "plushness" of a mechanical damping or braking system? For example, if a person or some mass is to collide with a fixed wall or the ground (e.g., after a vertical ...
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1answer
94 views

I have a pair of magnets that when I let go they attracted and broke

I let two magnets attract from a distance and when they hit they both broke a piece off of each-other. Why did the magnets damage each-other when they collided and is it possible to put the broken ...
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1answer
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Merging black holes — how fast do they hit?

Orbital mechanics says something falling from infinity hits at the escape velocity of the object it strikes. The escape velocity at the event horizon is lightspeed, it must be higher for the ...
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How do big black hole kicks out small black hole?

I read that when 2 black holes collide they will either merge into a single black holes or recoil and the less massive black hole will be thrown out, I'm thinking of gravitational slingshot whereby ...
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Why don't merging black holes disprove the no-hair theorem?

The no-hair theorem of black holes says they're completely categorised by their charge and angular momentum and mass. But imagine two black holes colliding. At some point their event horizons would ...
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1answer
84 views

Kinetic theory of gas. Pressure in a container derivation feels wrong

NOTE: Please Imagine A cube with 2 parllel faces I and II lying along the x axis. In the derivation what we are thought Change in the momentum of the molecule = Final momentum - Initial momentum =...
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1answer
418 views

How do I find the direction of impulse vector in a collision?

I know that impulse is the change in linear momentum. Is the direction of impulse always along the change in momentum vector? Please explain.
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In particle colliders, according to QM, how are two particles able to “collide”?

According to QM, we know that The act of measurement forces a particle to acquire a definite (up to experimental errors) position, so in a particle collider, like the one in CERN, by which means ...
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Pion decaying energy

The question is: A pion decays into a muon and a neutrino (which is almost massless, so we’ll take it to have a mass of zero). If the pion is initially at rest, find the energy of the outgoing ...
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68 views

Is it correct to use Newton's third law on all these scenarios? [closed]

So I was thinking about Newton's third law for sometime lately, and my problem is more about the concept, I'm fine with solving problems. I thought of these scenarios and tried to apply Newton's three ...
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1answer
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Two solutions of collision problem. Which is correct?

I'm solving a 1D problem, in which a particle with mass 2m collides elastically with a particle of mass m. Both of them have a speed V. After setting up the equations I've reached a quadratic ...
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$F_n$ force between 2 objects in space

I am trying to do a research project for school where I'm trying to simulate the physical world in a computer environment. So far things have been working great but I have trouble understanding how ...
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Centre of mass collision

A proton with momentum 3 GeV in LAB frame of reference is difussed elastically by a stationary proton. The angle of diffusion of one of the protons, in the CM system is 10º, corresponding to a moment ...
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222 views

Two bodies, one with mass m and the other with very very huge mass (tending to infinity), moving with velocity v and -v (opposite directions) collide

Assumption: The bodies are moving on the same axis, along their center of mass, and the bodies are perfectly spherical. There is no loss of kinetic energy after collision. m2 >>> m1 v2 = -v1 Will ...
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3D perfectly elastic collision between two points

There is a high probability, I think, that this question is a duplicate of some other question ... but to may knowledge, it hasn't been posed in this exact manner: Assume we have 2 points, $P_1$ and $...
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Particle collision and mass relation [closed]

Is mass important in calculations when two particles are collide? or is only the charge that matters? is collision in microscopic world the same with macroscopic world?
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Collision between two objects where the center of mass never moves

I had the following problem: Image two cars approaching one another in opposite directions. The first car is twice as massive as the second car. They move so that the center of mass of the two-...
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1answer
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Momentum of projectile in the centre of mass frame in a two body system

The COM frame is defined as the coordinate system in which the centre of mass of the system is at rest. In the case of a 2-body system the center of mass coordinate is: $$\vec{R_{CM}} = \frac{M_A \...
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Why are there no excitations by collision for the visible transitions in the Franck-Hertz experiment?

The minima of the I(V) graph for a Neon Franck-Hertz tube are approximately 20V apart from each other, this is usually explained by the fact that excitation by inelastic collision happens at about 20 ...
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Solving elastic 2-dimensional collision problems where the resultant angle is not provided [closed]

Having real trouble with the question below that is part of my engineering course. I've sussed question 6 but making no headway with Q7. A ball of mass 0.2 kg collides elastically with a heavier ball ...
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Total energy, total momentum of two different balls [closed]

I have a ball out of plasticine thrown horizontally with speed $v$ on a steel ball that is attached from top to the ground on flexible straps in the middle (see picture). The mass of plasticine is $m$,...
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What makes a collision 2D?

In my mechanics course, we've covered 1D and 2D collisions. However, what physical factors determine whether a collision will be 1 or 2 dimensional? To make the question more precise, consider a ...
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Physics of a punch

So I have odd question revolved around karate and would love to know if my physics assumptions are correct. Basically I would like to know what equation to use to calculate the force of a punch when ...
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How would a fast-moving atom interact with a body? [closed]

I found this question on Quora: https://www.quora.com/Can-you-theoretically-shoot-an-atom-fast-enough-to-kill-its-target I think the Quora answer is good but incomplete, and it got me wondering what ...
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In a masses inelastic collision, K energy convert to heat but velocity remain same. we receive heat without losing velocity? how?

I have read the answer about the energy and momentum conservation question but I have a great question now! Imagine we have two masses which one of them is at rest and another move and collide to the ...
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Why does shooting a handgun accelerate a bullet to deadly speed without injuring the gun user's hand?

Momentum is defined by the product of mass and velocity. Now a projectile out of a gun has to have high velocity to penetrate a human body, as its mass isn't significant. But to reach this velocity, ...
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148 views

Surviving a fall into a balloon-filled pit [closed]

My brothers and i have been debating this question for years. If an average person fell at terminal velocity into the center of a pit that is 1 mile deep x 1 mile in diameter, and the pit is filled ...
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Why do the colloidial particles in a viscuous fluid stop (stroboscopically) moving below a treshold as described in the experiment below?

In a nice experiment (inspired by the renowned physicist G.I. Taylor), which can be seen in this video (around 12 minutes), Professor David Pine and Professor Jerry Gollub filled a Couette cell with a ...
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Inelastic momentum question: How to calculate velocity before the collision? [closed]

EDIT: NEVERMIND! MY APOLOGIES, I DID NOT READ THE QUESTION PROPERLY. I DID NOT SEE THAT IT SAID THAT THE GUY WAS STATIONARY. I was doing a practice physics question and stumbled upon a question ...
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101 views

Direction of force when ball strikes an edge

From the perspective of classical mechanics, when a ball strikes an edge of a box-like-object, as shown here what is the direction of the force from the ball on the object (assuming there is no ...
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1answer
42 views

Impact Flash? In Vacuum?

I was wondering, when you have a "hypervelocity impact" e.g. a meteor or Space Debris hitting a body in orbit, why do you get a "flash" of light and how large would the flash be for a given impactor ...
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Does the total kinetic energy change during an elastic collision?

If two balls of same mass with speed $v$ and $-v$ undergo an elastic collision, the kinetic energy will be the same after the collision as before. However, during the collision, does it also remain ...
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188 views

Conservation of kinetic energy in two dimensional elastic collisions

I have a question where two particles collide with each other in a non central way. Mass of particle 1 ($m_1$) is $1\text{kg}$ and its velocity $v_1$ is $5\text{m/s}$ (moving along the x-axis) ...
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367 views

Newton's cradle: why not twice the balls at half the speed? [duplicate]

For "Sinterklaas" (Dutch holiday) I got a Newton's cradle. I understand the basics of it, but a couple things bother me. If I drop one ball, one bounces off. If I drop two, two bounce off. Why, if I ...
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Collision response with spring physics in RK4

I'm trying to figure out what's in the title. I've gotten regular spring physics working and now I'm trying to do something similar with actual collisions (player character colliding with the ground ...

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