What is Collision: Definition and 1000 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.
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Hi again, I will re-write this on behalf of a request. I am struggling trying to derive these equations for a physics lab. The equations asked to derive are the equations that describe a perfectly elastic collision between objects of identical mass.
These are given to me...
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Hi,
I have a quick question regarding elastic and inelastic collisions. I preformed an experiment in my house with two large, heavy marbles. I rolled one horizontally towards a stationary one, recorded a video of the collision. I uploaded the video to Tracker software...
In an Elastic Collision in free space with no gravity or friction of two solid balls of radius r1 and r2 I need to calculate the momentum and kinetic energy of the induced spin with angular velocity w1 and w2 to solve for the Conservation of Momentum and Kinetic Energy.
Spin
Angular Velocity
w1...
I am stuck on this concept in my physics book where the author claims that in a low density ionic gas the average of the time between collision and average of the time taken from last collision in ions is same. He further states that the average time to the next collision is same as the average...
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Question: A body of mass M1=m moving with a velocity V1=v in the x-direction collides with another body of the same mass m2=m moving in the y-direction with the same speed V2=v The coalesce into one body during collision
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(a) Find the magnitude of the...
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A molecule of nitrogen has a diameter of 3.2 x 10-8 cm and can be ionized upon absorbing 14.5 eV. what potential must be applied to a parallel-plate ion chamber operating at a pressure of 50mm of mercury, and with an electrode separation of 3.0 cm, in order to produce...
First, let me apologize if I don't give you enough info. If I'm missing something, please let me know and I'll try to get the info.
Here is the set up: Car A is traveling West at 5 mph. Car B is traveling South at X mph. Car B strikes A on the rear quarter panel (centered on the rear tire)...
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Homework EquationsThe Attempt at a Solution
I have solved the first part already.
For the 2nd part, I am writing the relevant eqns.
Can I take motion of the plank as a pure rotation about the pivot ?
Quantities corresponding to pivot is subscripted by p.
Conservation of...
I have two point masses, m0 and mp, colliding (with no radii) in an Elastic Collision (no mass loss). One has initial velocity, V0i. The other has initial velocity, Vpi. How do I calculate the initial forces, Foi and Fpi then formulate the final forces, F0f and Fpf yielding the final...
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A block of mass, m, is dropped from height, h (above the plate), onto a plate of mass, M, which is attached to a spring with spring constant, k. The block sticks to the plate and the system starts to oscillate. What is the amplitude of the oscillations.
Homework...
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A billiard ball moves at a speed of 4.00 m/s and collides ELASTICALLY with an identical stationary ball. As a result, the stationary ball flies away at a speed of 1.69 m/s. Determine
a. the final speed and direction of the incoming ball after the collision
b. the direction...
Im learming physics through google and I would like to be able to simulate some simple physics prgromatically. Having a hard time with solving for velocites after an elastic collision. Consider two objects, each with a mass of 1kg. One at rest and the other with velocity of 1 m/s in the...
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The particle J/Ψ can be produced in both proton-proton collisions and electron-positron collisions.
a) Consider a proton beam incident upon a fixed hydrogen target. Calculate the energy of the proton beam in the reaction
p1 + p2 → p + p + J/Ψ
b) Consider two counter...
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A particle of mass m and and velocity v collides with a square of mass M (at rest)whose movement is confined to rotation about its centet. I must now solve for the angular velocity and the velocity of the particle after the collision (elastic collision)
Homework Equations...
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Two cars of 540 kg and 1400 kg collide head on while moving 80 km/h in opposite directions. After the collision, the automobiles remain locked together.
Find the velocity of the wreck, the kinetic energy of the two-automobile system before and after the collision, and find...
1. Homework Statement
A projectile of 45kg has a muzzle speed of 656.6 m/s when fired horizontally from a gun held in rigid support (no recoil). What will be the muzzle speed (relative to the ground) of the same projectile when fired from a gun that is free to recoil? The mass of the gun is...
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Homework Equations
I have thought about using the momentum formulas here.
The Attempt at a Solution
As the momentum is a conservative quantity, I have thought that p (before collision) = p(after collision).
Since p (before collision) = 12, I wanted to use that result to...
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Two blocks move along a horizontal frictionless surface and collide head-on with each other. The mass of the first block, moving to the right with speed v is m, and the mass of the second block moving towards the left with speed 3v is 2m. After the collision, the block of...
I wonder if it is possible to at least estimate the stress (or the impact force) that the cube in question will experience due to the collision with the concrete floor. Assumptions:
1. The cube is dropped from height h
2. The cube is relatively small, thus we can neglect air resistance...
For an inelastic impact situation where two bodies traveling in opposite directions (vehicles say) collide and coalesce (perfectly inelastic collision) , one can derive the following expression for equal and opposite transfer of momentum. On the basis that if impact forces are equal and...
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The Problem is the following: We have a uniform disk of radius r laying still with its center at the origin. Two bullets, with equal mass m and negligible size are approaching the disk, both with trajectories parallel to the x-axis and at distance h, -h from the y-axis...
https://www.physicsforums.com/attachments/upload_2017-6-17_4-22-26-png.205585/?temp_hash=f9f8d75085046fd530ad1071794d65c1
I have problem with the solution given of the (b) part of the question.
The given solution is :
I did not understand why the value of ##\Delta T = 2x/v## even when...
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Small object A (mass: [m][/A]) is traveling in a linear path on a horizontal surface and collides elastically with small object B ([m][/B]), at rest on the same line, with a speed of v. Friction between the objects and the horizontal surface is negligible.
What is the...
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A sphere of radius R is rolling without slipping with a velocity v and collides inelastically with a step of height h < R. ¿What is the minimum velocity for which the sphere will be over the step?
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Total kinetic energy (maybe)...
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In a particle physics lab, an electron e− and a positron e+ collide, annihilate, and produce a W+ boson and a W− boson. Just before the collision, the electron and positron have a total energy of E = 100 GeV each, with velocities pointing along the +x-axis and -x-axis...
In my experiment I am performing a collision with two carts with magnets attached with photogates and a labquest on an air track. I pushed the carts together and made sure that the carts did not come into contact. Based on my knowledge of collisions, I believed that the collision would have been...
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Two photon (wavelengths 1pm, 2pm) collide, decaying into a pair positron-electron find the velocities of these particles
Everything happens in the x axisHomework Equations
The system
hc(1*1012+0.5*1012)=E++E-
h(1*1012-0.5*1012)=P+-P-
E=sqrt(c2P2+m2c4)The Attempt at a Solution...
I have 2 ellipsoids:
Ax^2/a^2+Ay^2/b^2+Az^2/c^2=1; (*a,b,c>0 constants*)
Bx^2/a^2+By^2/b^2+Bz^2/c^2=1;
Ellipsoid A rotates around axis [wax;way;waz] (unit vector) with an infinite speed;
Ellipsoid B rotates around axis [wbx;wby;wbz] (unit vector) with an infinite speed;
[Dx;Dy;Dz] is the vector...
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Please see the attached photo. (down)
Hminitial= 1.5R
M = 2/3m
Perfectly elastic collision
What is the velocity of object m immidiatly after the collision? (by m,g,R)
Homework Equations
Conservation of energy
Conservation of momentum
The Attempt at a Solution
I assumed...
Hi all,
I am currently self teaching physics and have come across something i don't know how to do.
There are 2 cars, Cars 1 and 2, traveling at a velocity of 60km/h (16.67m/s) in the eastern direction with a gap of 5 metres between each other. Car 2 is in front of Car 1. Car 2 decelerates to...
Dear all,
I am working on a car-accident prediction model. I found the following equations here that worked in my model. However, I could not figure out how the equations were derived. Could anyone help me in understanding the derivation of the mintime and mindist equations (Steps 3 and 5...
I have read in textbook that if a photon were to collide with a free electron it's an impossible situation for photon to get completely absorbed by an electron .
The situation seems possible by conservation of energy but I am not able to understand the true reason behind the statement .is there...
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A body X moving with a velocity v makes an elastic collision with a stationary body Y of equal mass on a smooth horizontal surface. Which statement gives the velocities of the two bodies after the collision? (multiple choice question)The Attempt at a Solution
The answer...
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This is not really a homework problem, just me trying to get a ballpark number for a random problem.
Suppose I have a neutron flying at some energy and it hits an oxygen atom. If the oxygen atom, after the collision, now has 20 keV of energy, but before, had ~ 0, is there a...
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Car 1: 2200kg
Initial direction: South
Car 2: 1800kg
Initial direction: East
Cars lock together and slide 11.25M (S 22.25 E)
At an acceleration that is 9.81 m (back) (it's a coincidence that this is gravity.)
Homework Equations
Who's fault was the collision if the speed limit...
1. Homework Statement
a point mass is projected at an angle of 60° from the horizontal. it collides with the sphere at a maximum height of trajectory with a sphere of radius of 72.5cm such that it is projected off the sphere once again at an angle of 60° from the horizontal.The sphere, due to...
During a collision between a truck and a wall, an occupant of the truck is thrown forward because of inertia; he continues moving forward. Why does the occupant stop eventually? What is the resultant force that opposes his forward motion? Is this force the equal and opposite normal reaction...
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The figure shows an overhead view of a 2.50-kg plastic rod of length 1.20 m on a table. One end of the rod is attached to the table, and the rod is free to pivot about this point without friction. A disk of mass 39.0 g slides toward the opposite end of the rod with an initial...
Two chunks of rock, each having a mass of 1.00 kg, collide in space. Just before the collision, an observer at rest in the reference frame of a nearby star determines that rock A is moving toward the star at 0.800 c and rock B is moving away from the star at 0.750 c .
If the rocks stick...
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Show that if an elastic collision between a mass and a stationary target of equal mass is not head-on that the projectile and target final velocities are perpendicular. (Hint: Square the conservation of momentum equation, using ##p^2=p\cdot p##, and compare the resulting...
Suppose there are two objects, denoted by A and B. When they collide with each other with the condition that A is stationary and B is in motion, B exerts an action force on A due to which A exerts a reaction force on B. Thus the net force exerted on A is FactionAB and the net force exerted on B...
Hi - I know that the information that I can provide here is too limited for a totally accurate answer, but is it possible to come up with a reasonable estimate? One vehicle, snow tires, on dry pavement, 6 degrees celsius, is motionless. Second vehicle strikes first in the rear. No evidence of...
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photon collides with an electron producing a electron-positron pair, the three particles ( two electrons and one positron) move together in the same direction of the original photon.
calculate the energy of each particle.
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photon:
Ep=hf...
I recently came across https://www.physics.uoguelph.ca/~jlhunt/morph/5exp.pdf paper in The Physics Teacher that describes a handful of experiments which can be performed with common materials. The collision experiment in particular caught my eye because it seems like most collision experiments...
Hi! I am new to the forums and this is my first question.
I am investigating the properties of this type of chain.
In order to understand it better, I need to know the physics behind a falling angled rod.
I understand that the other end speeds up to conserve momentum, but I do not understand...
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A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m/s. It hits the floor of the elevator (length of the elevator = 3 m) and does not rebound. What is the heat produced by the impact ? Would your answer be different if the...
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A photon with the length of lambda hits a cathode perpendicularly to its surface. As a result, an electron leaves its surface perpendicularly to the direction of the photon. How much momentum was transferred from the photon to the cathode? The work function of the cathode is...
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A small wooden block with mass 0.800 kg is suspended from the lower end of a light cord that is 1.60 m long. The block is initially at rest. A bullet with mass 0.0132 kg is fired at the block with a horizontal velocity v-_i. The bullet strikes the block and becomes embedded...
Most Fusion reactors, and the leading ones like JET, use high temp. plasma and confine it. So, the plasma would approximate the Maxwell- Boltzmann distribution. This means that only a small portion of the plasma has enough energy to fuse. But, collisions are much more often, right? Since not all...