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.
Homework Statement
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Two cars are approaching a perpendicular intersection without a stop sign. Car 1 has a mass ## m_1 = 900 kg ## and is heading north at ##v_1 = 25 m/s ##. Car 2 has mass ##m_2 = 700 kg ## and is heading west at an unknown speed ##v_2##. The two cars collide at the...
So a truck hits a car, which is at rest.
Would there be a moment in time when a car stops exerting a force in equal magnitude but in opposite direction (Newton's third law)?
To put in some arbitrarily numbers to make the example easier to understand.
Truck weighs 1000 kg, and the car weighs...
A bullet is fired directly into a wood block (along the x-axis), which rests on a rough table. The bullet embeds itself in the block. (This is an inelastic collision: the block deforms and the block and bullet heat up as a result of the collision).
a) If the bullet has a mass 0.049kg and is...
A particle of mass m comes with the speed 0.6c and collides with another particle of mass m which is at rest. In the collision melts the particles together and form a particle. What is the mass and velocity of the particle is formed?
solution:
The momentum and the total energy is conserved...
1. The problem statement, all variables and given/own data
http://prntscr.com/661d5d
Homework Equations
m1v1 + m2v2 = m1v1p +m2v2p
The Attempt at a Solution
I asumed that the momentum in the y direction is constant, and that in the x direction it is conversved.
Also, i thought of it as 2 parts...
Hey Guys, Can you tell me how to solve this one, Need not give me direct answers but just take a look at this :
Consider two disks A and B of equal radius, let m1 be the mass of disk A and m2 be the mass of disk B, Both are moving towards each other with Velocity v1 and v2 respectively, If they...
Homework Statement
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Two rocks collide in outer space. Before the collision, one rock had mass 14 kg and velocity ‹4450, −2950, 2250› m/s. The other rock had mass 7 kg and velocity ‹−600, 1900,3600› m/s. A 1 kg chunk of the first rock breaks off and sticks to the second rock. After the...
Hi,
I've been trying to understand a simulation for a collision cascade. The PhD that produced this code says that he is modelling a 10keV collision in Fe. From this he says that his PKA velocity is 2620.579 ang/ps or 262057.9 m/s and I'm wondering how did he get this?
I've assumed that the...
Homework Statement
In this problem, you will estimate the cross section for an earth-asteroid collision. In all that follows, assume that the Earth is fixed in space and that the radius of the asteroid is much less than the radius R of the earth. The mass of the Earth is M_e, and the mass of...
Homework Statement
A particle and its anti-particle are directed toward each other, each with rest energy 1,000 MeV. We want to create a new particle with rest energy 10,000 MeV and total energy 100,000 MeV. What must the speed of the particle and antiparticle be before the collision.
ERest0 =...
Homework Statement
A large sphere rests on a rough horizontal ground,
A ball of mass 'm' is thrown towards it along one of its radius at a speed 'u' , along an angle 'x' with the vertical
Find the angle with the vertical at which the ball should strike (find x) so that the large sphere pure...
Homework Statement
a ball of mass 0.1 kg, is free falling from the height (h1) of 1 m. hits the ground with a k = 0.5.
##k=\frac{v_2}{v_1}##
A)Height that the ball will reach after the hit.
B)The heat quantity released by collision
Homework Equations
I think ##mgh## and ## \frac{mv^2} {2} ##...
Hi all x I'm doing some physics related code for a game in unity engine. Unity does have a very full featured physics engine, but i can't utilise it in certain circumstances.
I have a wall made up of pre-fractured little chunks, and each chunk has a connective strength which represents how...
Homework Statement
I am not asking you to help me solve this, so i won't put in any usefull relevant equations or attempts at a solution. The nature of my problem is more of an understanding this collision - it is more of a thinking thing to process here.
The problem goes like this.
Ball is...
Homework Statement
Two frictionless pucks are placed on a level surface with an initial distance of 20.0 m. Puck 1 has a mass of 0.80 kg and a charge of + 3 E-4 C while puck 2 has a mass of 0.4 kg and a charge of +3 E-4 C. The initial velocity of puck 1 is 12 m/s [E] and the initial velocity...
Homework Statement
A thin target of lithium is bombarded by helium nuclei of energy E0. The lithium nuclei are initially at rest in the target but are essentially unbound. When a Helium nucleus enters a lithium nucleus, a nuclear reaction can occur in which the compound nucleus splits apart...
Homework Statement
2 cars of equal mass and traveling in opposite directions on a wet and slippery road collide and lock together after impact. Neither car brakes before the collision. The tangled wreck moves off in an easterly direction at 5 m/s immediately after the collision. if one car was...
Homework Statement
Particle A of mass m has initial velocity v0. After colliding with particle B of mass 2m initially at rest, the particles follow the paths shown in the sketch (see attachment). Find ##\theta##
Homework Equations
collisions
The Attempt at a Solution
The momentum before and...
I'm developing a 3 Dimensional android car game, so i need a formula to calculate the damage of the car after colliding the tree, wall or signal.
I have velocity and mass of the car and also i have the mass and velocity of the colliding object. I use inelastic collision formula for signal and...
Homework Statement
Cars B and C are at rest with their brakes off. Car A plows into B at high speed, pushing B into C. If the collisions are completely inelastic, what fraction of the initial energy is dissipated when car
C is struck? The cars are identical initially.
Homework Equations...
Homework Statement
A small ball of mass m is placed on top of a “superball” of mass M, and the two balls are dropped to the floor from height h. How high does the small ball rise after the collision? Assume that collisions with the superball are elastic, and that m<<M. To help visualize the...
Homework Statement
A cart of mass m moving at 12 m/s to the right collides elastically with a cart of mass 4.0 kg that is originally
at rest. After the collision, the cart of mass m moves to the left with a velocity of 6.0 m/s. Assuming an elastic
collision in one dimension only, what is the...
Homework Statement
A thin rod AB of mass ##m_{1}## and of length ##l## is placed on a smooth horizontal ground. A point sized particle of mass ##m_{2}## having a velocity ##v## making an angle ##\theta##with the line perpendicular to ##AB## collides with the rod at point ##A##.
Assuming the...
Homework Statement
(a)Find energy of photon emitted
(b)Show that relative velocities after de-excitation are reversed
(c)Find an expression for CM frame energy and find momentum of either particle in CM frame
(d)Consider now, for a nuclear process and describe the initial and final conditions...
So I was wondering if anyone could help me out. I am trying to find a way to calculate the cascade volume in a steel alloy undergoing ~ 1 MeV ion irradiation ( Z ~ 25). For this analysis I will be looking at the electronic stopping regime with PKA energy of ~ 10 keV. Not sure what to do after...
1. Situation: I have no specific exercise in mind but just the general form. ''A beam of protons is colliding with a plate of a given particle density ##\rho## and thickness ##l##. The cross section is ##\sigma##. What should the thickness of the plate be such that the intensity of the outgoing...
Homework Statement
Derive an expression for the mean collision time in a gas where the collision cross-section is σ and the number density is n.
The Attempt at a Solution
I'm just using my book to do this, and I can't get past the first bit...
It says
Consider a particular molecule moving at...
[Moderator's note: No template because the thread had attracted a fair number of responses before being moved out of Classical]
Hey it's my first post, so I apologize in advance if this is under the wrong forum category... I am just wondering if I did I do this right? If not can you please...
Hello, I am preparing for the IIT JEE exam, The toughest entrance exam in the Indian subcontinent, and i am struck in confusion about the theory regarding waves in Physics. The problem is that I can;t visualize the sine-cos functions physically , as I could visualize the movement of pulley...
Homework Statement
This is a solved problem--
http://web.mit.edu/8.01t/www/materials/InClass/IC_Sol_W13D1-10.pdf
Homework EquationsThe Attempt at a Solution
In the solution, they conserve energy and angular momentum. Can I conserve linear momentum? Also, can I use coefficient of restitution...
Homework Statement
A uniform disk of radius R=1m rotates counterclockwise with angular velocity ω=2rads/s about a fixed perpendicular axle passing through its center. The rotational inertia of the disk relative to this axis is I=9kg⋅m2. A small ball of mass m=1 is launched with speed v=4m/s in...
Homework Statement
I am doing this project and it asks me for the before and after velocity of a inelastic collision.
Homework EquationsThe Attempt at a Solution
I have found the before velocity of both object which is 0 and 15 m/s, however i am trying to find the after velocities right now...
Hey! :o
I want to write a function for the collision of the free-floating planet with identifier ffp and the planet with identifier as. The collision has as a result the destruction of both planets. Specifically, the free-floating planet with identifier ff will be deleted from the free-floating...
Consider a particle with velocity "v" has the collision with a rotating disc.
How can I analyze the final angular velocity this system?
If the mass of particle is very negligible related to the mass of rotating disc, definitely particle will turn back after collision. In this case, how can I...
Homework Statement
Pete got into into a car accident and collided with another vehicle, which resulted in the death of the second vehicles passenger, David. Whether Pete was speeding or not determines if he goes to jail. The speed limit where he got into the accident was 45mph. How fast was...
Homework Statement
In a collision between two unequal masses, how does the impulse imparted to the smaller mass by
the larger mass compare with the impulse imparted to the larger mass by the smaller one?
A) They are equal.
B) It is larger.
C) It is smaller.
D) The answer depends on the ratio of...
Homework Statement
A 6.64-g bullet is moving horizontally with a velocity of +340 m/s, where the sign + indicates that it is moving to the right. The bullet is approaching two blocks resting on a horizontal frictionless surface. Air resistance is negligible. The bullet passes completely through...
Homework Statement
calculate the mass of an unknown nucleus of mass M_X (initially at rest) if it it is hit by an alpha particle of mass m_xand is deflected by 40 degrees, and the alpha particle is deflected by an angle of 70 degrees.
Assume elastic collisions
[/B]Homework Equations...
Homework Statement
Two objects of equal mass traveling toward each other with equal speeds undergo a head on collision. Which one of the following statements concerning their velocities after the collision is necessarily true?
(a) They will exchange velocities. (d) Their...
Hi,
Suppose I perform a basic experiment of an elastic collision between 2 carts. I do not want the carts to touch each other so I adjust a permanent magnet to each cart and give each one a starting velocity. Carts get close to each other, kinetic energy is transformed into "potential magnetic...
1.Problem: An electron with energy ##E## which is much higher than its restmass collides with a much much heavier particle "A" of mass ##m## which is at rest. Find the maximal transfer of four-momentum. (Elastic collision)2. Conservation of four momentum3. Everything in natural units. So I go...
1. An asteroid is 10r away from the earth, and traveling at a speed of 12 km/s. What is the impact speed of the asteroid when it hits the earth?2. Gravitation problem: U = -Gm[E]m / r ...I think3. I've been looking in my book and online and cannot figure it out, please help!
Homework Statement
Cart 1 on ball-bearing wheels is moving at 4m/sec. It rolls down the hill and hits a stationary cart 2. The collision is elastic. The height of the hill is 1.02 m. Mass of Cart 1: 200 grams; Mass of Cart 2: 400 grams: Find the velocity of cart 1 at point B. [/B]
Homework...
Homework Statement
A 100g ball moving to the right at 4.1m/s catches up and collides with a 400g ball that is moving to the right at 1.0m/s .
a)If the collision is perfectly elastic, what is the speed and direction of the 100g ball after the collision?
b)If the collision is perfectly elastic...
Homework Statement
After a lot of searching I can't seem to find a way to solve this. Basically, for a bouncing ball, if I know the dropped height and rebound height in a vacuum. How do I calculate the elasticity between the ball and the floor?
Homework Equations
K = 1/2 mv2
The Attempt at a...
This is a modified problem from the one posted a few days ago. I’ve been unsuccessfully trying to solve it since then, so maybe it’s time to ask for some help.
I’ve changed the quantities :)
1. Homework Statement
The mass of puck 1 is ##0.2\ kg## and that of puck 2 is ##0.25\ kg##. The...
Homework Statement
The first ball collides with ##v_1## collides with the second two as shown in the picture. All balls are identical and the second balls have no speed at the beginning.
Find the transform matrix and find the covariation matrix after the collision if it is ##
\begin{bmatrix}...
So I'm upgrading my Physics Engine's Collision response system (don't worry, this is a pure physics question, no programming involved! Also don't worry about the time of collision, my collision detection system is separate and returns a time of collision for the response system to work with) and...