What is Collisions: Definition and 706 Discussions
In physics, a collision is any event in which two or more bodies exert forces on each other in a relatively short time. Although the most common use of the word collision refers to incidents in which two or more objects collide with great force, the scientific use of the term implies nothing about the magnitude of the force.
Some examples of physical interactions that scientists would consider collisions are the following:
When an insect lands on a plant's leaf, its legs are said to collide with the leaf.
When a cat strides across a lawn, each contact that its paws make with the ground is considered a collision, as well as each brush of its fur against a blade of grass.
When a boxer throws a punch, their fist is said to collide with the opponent's body.
When an astronomical object merges with a black hole, they are considered to collide.Some colloquial uses of the word collision are the following:
A traffic collision involves at least one automobile.
A mid-air collision occurs between airplanes.
A ship collision accurately involves at least two moving maritime vessels hitting each other; the related term, allision, describes when a moving ship strikes a stationary object (often, but not always, another ship).
In physics, collisions can be classified by the change in the total kinetic energy of the system before and after the collision:
If most or all of the total kinetic energy is lost (dissipated as heat, sound, etc. or absorbed by the objects themselves), the collision is said to be inelastic; such collisions involve objects coming to a full stop. An example of such a collision is a car crash, as cars crumple inward when crashing, rather than bouncing off of each other. This is by design, for the safety of the occupants and bystanders should a crash occur - the frame of the car absorbs the energy of the crash instead.
If most of the kinetic energy is conserved (i.e. the objects continue moving afterwards), the collision is said to be elastic. An example of this is a baseball bat hitting a baseball - the kinetic energy of the bat is transferred to the ball, greatly increasing the ball's velocity. The sound of the bat hitting the ball represents the loss of energy.
And if all of the total kinetic energy is conserved (i.e. no energy is released as sound, heat, etc.), the collision is said to be perfectly elastic. Such a system is an idealization and cannot occur in reality, due to the second law of thermodynamics.
Consider the case in which an incoming particle collides with stationary target particle producing new particles through the interaction. For example, $$e^{-}+e^{+}\rightarrow X+\bar{X}$$ My question is, why in general do the particles produced in such an interaction propagate outwards are...
Just watched a Youtube of a TV show about "weird planets". They show early on a collision between two planets, proportioned about the same as the Earth and the Moon. The interesting thing is that they show part of the "Earth" being pulled up to meet the "Moon."
Could this happen? Could it...
The book I'm reading (Spacecraft Systems Engineering) says that there are very few atomic/molecular collisions between components of the atmosphere and spacecraft in LEO or GEO, which means that any heat exchange comes from radiation alone, and the path of the orbit can be modeled as free...
Hi there,
A friend of mine is creating a physics engine in java (mostly as a challenge I believe).
Today he asked me a question about the results of collisions between objects. For example, imagine that these 2 objects collide:
The results of such a collusion would be something like this...
Homework Statement
Three perfectly elastic particles A, B, C with masses 4 kg, 2 kg, 3 kg respectively, lie at rest in a straight line on a smooth horizontal table. Particle A is projected towards B with speed 15 m/s and after A has collided with B, B collides with C. Find the velocities of the...
Homework Statement
Why is there more heat and sound energy produced with a larger collision?
Homework EquationsThe Attempt at a Solution
Honestly no clue. I would really appreciate any help! Any videos would also help!
Homework Statement
A low-energy particle collides elastically with a stationary particle of the same mass. The angle between the subsequent paths of both particles are 90 degrees.
But when a high-energy proton collides with a stationary proton, the angle between the two paths is not 90 degrees...
Sometime ago, in my partial state of sleepiness and being awake (you could call it trance - yo!) I had a thought that during perfectly elastic collisions, it's the deformation of the colliding particles which transfer energy from one to the other. But doesn't that assume that there are empty...
I am taking a physics modeling class and for our projects we need to add in some element to our physics engine that is unique and different. I choose to model the deformation of objects as a result of collisions.
For clarification, When things bounce, I want to know by how much do they...
Homework Statement
a small 0.199 kg block slides down a frictionless surface through height h = 0.608 m and then sticks to a uniform vertical rod of mass M = 0.398 kg and length d = 2.23 m. The rod pivots about point O through angle θ before momentarily stopping. Find θ.
point O is at the end...
Consider a collision between two point particles, with no external forces acting on the system.
Linear and angular momentum of the system are always conserved, while the kinetic energy of the system is conserved only if internal forces acting in the collision are conservative. This last point...
Homework Statement
Two balls with the same mass are dropped from the same height. After colliding with the ground, one of the balls "A" bounces higher than the other ball "B." Neglect air resistance.
Is mechanical energy conserved ?
Are they subjected to the same impulse after colliding with...
The problem:
A beam of electrons with kinetic energy 12.8 eV collides with a hydrogen target. What visible spectral lines will be emitted due to collisions?
My question:
I am confident I know how to do the bulk of this question, I am just uncertain about one thing: I know that 12.8 eV is enough...
Homework Statement
Find the initial velocity of an alpha particle with a mass of ##6.64 \times 10^{-27} kg## and a charge of ##+3.2 \times 10^{-19} C##, if it undergoes a head on "collision" with a gold nucleus. You may assume the gold nucleus does not move at all during the interaction. The...
Homework Statement
In a closed system, in an inelastic collision, momentum and total energy is conserved, but total kinetic energy is not.
But how is this possible? If we have a change in total kinetic energy, we have a change in velocity, and so we must have a change in momentum as...
Homework Statement
You have an inertia of 52 kg and are standing at rest on an iced-over pond in your skates. Suddenly, your 60-kg brother skates in from the right with x component of velocity -4.9 m/s and collides elastically with you.
1. What is the siblings' relative speed after the...
Hi.
The formulae for the velocities of two bodies after a perfectly elastic or inelastic bodies, let's say in 2D, (e.g. billiard) can be derived from three equations: conservation of energy and conservation of momentum in two dimensions.
But how do you treat collisions of three or more bodies...
Homework Statement
One mole of oxygen at 27°C and at one atmospheric pressure is enclosed in a vessel.
Assuming the molecules to be moving with Vrms, find the number of collisions per second which the molecules make with 1 m2 area of the vessel wall.
Homework Equations
vrms = √(3RT/M)
PV = nRT...
Homework Statement
A 2.00-kg object is attached to an ideal massless horizontal spring of spring constant 100.0 N/m and is at rest on a frictionless horizontal table. The spring is aligned along the x-axis and is fixed to a peg in the table. Suddenly this mass is struck by another 2.00-kg...
Homework Statement
Two equal mass hockey pucks undergo a glancing collision. Puck 1 is initially at rest and is struck by puck 2 traveling at a velocity of 13 m/s[E]. Puck 1 travels at an angle of [E18N] after the collision. Puck 2 travels at an angle of [E4S]. Determine the final velocity...
Please be patient with my ignorance. :)
I have just learned in the LHC's own website ( http://lhc-machine-outreach.web.cern.ch/lhc-machine-outreach/beam.htm ) that their proton beams traveling at 0.999999991c carry about 362 MJ of energy, equivalent to 77.4 kg of TNT. These beams seem to be...
Hello everyone, here's the problem
Homework Statement
A pole with mass m2 = 2 Kg is planted on the ground with a consecutive hammer hits. The hammer ha a mass m1 = 4 kg and is dropped from 1 meter upon the pole. With a single hit the pole penetrate the ground of 2 cm.
Find:
a) the total...
Homework Statement
EDIT: DO NOT READ. I SOLVED IT.[/B]
The collision in this problem acts at point C and acts a purely horizontal force in the inertial frame of reference.
Homework Equations
The Attempt at a Solution
I understand the maths that is at work here, when we resolve the force...
A 2-kg ball is moving at 3 m/s toward the right. It elastically collides with a 4-kg ball that is initially at rest. Calculate the velocities of the balls after the collision.
I know that kinetic energy is conserved in elastic conditions, but I don't know how to use that to calculate this. I...
I'm using Chaisson'/McMillan's "Astronomy, a Beginner's Guide to the Universe"/7th Edition
In Chapter 7, it describes the gas giants, and says that Jupiter, Uranus, and Neptune all have "86% Hydrogen, 14% Helium" in their atmospheres, while Saturn has about 92% hydrogen, and 7% Helium, in its...
Homework Statement
Three particles, A, B, and C, with masses M, 2M, and 3M respectively, lie at rest in that order in a straight line on a smooth horizontal table. The particle A is then projected directly towards B with velocity U.
Assuming the collisions are perfectly elastic, I need to find...
Homework Statement
A ball with the mass 0.48kg is hanging on a string. The ball is moved to the side and then released . When the string is vertical, the ball hits the side of a block which is at rest . The ball's position is then 1.5 lower down than from the beginning.
a) the speed gets the...
Hi all!
I'm developping a program, I wish if somebody helps me since I'm not good in physics, we know that:
v'1=v1-(j / m1)*n
v'1=v2+(j / m2)*n
1) when we use negative and positive sign? if we change them, there is error sometimes.
2)In 2d, do I have to calculate vx, and vy separately, what...
How do collisions occur between different particles when the field excitements that make them are not the same? Also how do you collide when the field are the same? Wouldn't the values of the field just increase until the particles pass through each other? (Like a constructive wave). What I mean...
Homework Statement
A small mirror of area A and mass m is suspended in a vertical plane by a weightless string. A beam of light of intensity I falls normally on the mirror and the string is deflected from the vertical by a very small angle A. Assuming the mirror to be perfectly reflecting, to...
Homework Statement http://www.pdx.edu/physics/sites/www.pdx.edu.physics/files/Nov-19th_version_Comprehensive%20Exam%20I_Nov-2006.pdf
Homework EquationsThe Attempt at a Solution
This problem is driving me nuts. Its the problem number 1 in the afternoon session exam provided in the link above...
Homework Statement
One end of a spring is attached to a wall to a block of mass X= 2kg (on a frictionless horizontal table). Another mass M of 150g moving at a speed of 7m/s collides (inelastic). This takes 0.4s to compress the spring to its max compression.
I have to find the max force of...
Homework Statement
The problem and solution is here: http://nebula.deanza.edu/~Newton/4A/4AE2P3Winter10.jpg .
Homework Equations
The equations are in that link.
The Attempt at a Solution
My question is how do you know that the final velocities of both masses are equal to each other? wouldn't...
Today is an exciting day, for today will see a new record for the highest energy collisions at the LHC - stable 13 TeV collisions for new physics, signalling the start of the new physics program at the LHC!
There are a few ways you can keep track of progress throughout the day.
The LHC status...
Homework Statement
A particle (of mass m velocity v) makes a perfect elastic collision with a stationary particle. After the collision both particles travel 30 degrees from original path. Use conservation of momentum/energy to obtain 3 equations relating the masses/velocities.
Homework...
I have a paradox here.
Look at this diagram of colliding ellipses (they might be elliptical prisms in 3D). Now if you stretch the image (for example looking at the image from an angle) it becomes two colliding circles. Therefore you would expect by that argument that the colliding force would...
Homework Statement
There are two trolleys traveling in the same direction which are about to collide.
Trolley 1 is traveling at 4 metres per second and has a mass of 2kg
The other, Trolley 2, (which is in front) is moving a 1 metre per second and has a mass of 4kg.
After the impact, they...
Homework Statement
A lorry of mass 20,000kg is traveling at 20.0 metres per second. A car of mass 900kg is traveling at 30.0 metres per second towards the lorry.
What is the magnitude of the total momentum?
1. 209 kNs
2. 373 kNs
3. 427 kNs
4. 1045 kNs
2. Homework Equations
Linear Momentum...
I did a quick search through the forums and didn't find the answers I was looking for, so I thought I'd ask. Does charge conservation still apply for collisions between elementary particles? I'm taking a second year foundations of physics course, and we were given a fairly simple looking...
We know that the ratio of velocity of separation to the velocity of approach of two bodies in a head on collision is called coefficient of restitution .Is there no possibility that the velocity of separation is quite larger than that of approach? or vice versa? can't the ratio be more than 1 or...
http://www.nasa.gov/press/2015/march/nasa-s-hubble-chandra-find-clues-that-may-help-identify-dark-matter/index.html
The take away seems to be that some ideas about dark matter may have problems. The possibilities checklist of dark matter interactions has been shortened.
There are some really...
Homework Statement
Two hockey players push each other on the ice. The 86-kg skater moves with a velocity of 2.4 m/s. Find the recoil velocity of the 79-kg skater
Homework Equations
idk
The Attempt at a Solution
86*2.4=79*v2 v2=2.613 m/s
Second problem
Homework Statement
A child drops a 5-g...
Homework Statement
Hi everyone,
So I am asked to detect the number of neutrino events that occur from them entering 3000 metric tonnes of pure water. I am given that t=10s , E(neutrino)=10MeV and that the electron cross section is 10^-47 m^2 . This was the famous neutrino experiment at...
Homework Statement
A block of mass m1=2.0 kg slides along a frictionless table with a speed of 10 m/s. Directly in front of it, and moving in the same direction, is a block of mass m2=5.0 kg moving at 3 m/s. A massless spring with spring constant k = 1120 nt/m is attached to the backside of m2...
Hi,
Basically I have a point cloud that represents balls with different radii. They are all moving based on forces and sometimes they are intersecting with each other.
Imagine the yellow ball is going in one direction while the blue balls goes in another direction. At one time they are...
Homework Statement
We have a particle mass ##m## with kinetic energy ##k## colliding with a stationary particle of mass ##2m##. The collision creates a composite mass of ##\sqrt{17}m##. Find the value of ##k##
Homework EquationsThe Attempt at a Solution
I have tried using mass-energy...
I am constructing a linear particle accelerator and have come into a problem, I need a materiel that when a electron hits it the electron breaks apart in smaller particles and the materiel breaks apart (on the subatomic level of course) as little as possible and make a little exes radiation as...
I am trying to calculate differential cross-section for partonic collisions (QCD) like
q + q \rightarrow q +q
q + \bar{q}\rightarrow q + q
g + g \rightarrow g + g
I can't find those calculations done anywhere, just the results and maybe some middle tips, that's all. As you may know those...
Homework Statement
A diesel engine weighs 8 times as much as a freight car. This diesel engine, moving on a horizontal track at 3 km/h, crashes into the freight car (which was moving at 2 km/h in the same direction). What is the velocity, in km/h, of the now linked together engine/car...