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.
1) The Hilbert space for each particle and the system are:
##H_1={\ket{\frac{1}{2} \frac{1}{2}}; \ket{\frac{1}{2} -\frac{1}{2}}}##
##H_2={\ket{1 1}; \ket{1 0}; \ket{1 -1}}##
##H=H_1 \otimes H_2##
2) I'm not sure what "considering the total Hamiltonian" means, but I think that the two CSCO...
Teacher described the Thomson scattering effect through the lens of the electric field changing as a moving particle is accelerated. The changing electric field of the electron accelerating carries with it an amount of energy, and this energy radiates out from the acceleration event. (there were...
Hello,
I need some articles and pictures about secondary particle generation when x-ray(with different energy) collides with silicon and aluminium materials. I am simulating this phenomenon in geant4. I just want to validate my result.
Kinetic energy before collision =1/2 mv² + 1/2 mv² = mv² (since energy is a scalar quantity, the direction does not matter). Kindly tell why am I not getting the required answer i.e: 1/2 mv². Am I doing the calculation wrong?
Attempt:
Denote ## T## as the hash table, ## h ## as the hash function.
Denote ## n ## as the number of keys in the universe, and ## m ## as the size of hash table.
Order the set of keys from the universe as ## \{ k_1 ,..., k_n \} ## such that ## k_i \leq k_j ## where ## i \leq j ##.
Note...
(The equation of ideal gas is PV=NRT.if P=1atm,N=1mole,T=0°K,R=gas constant then volume = zero. Hence, the volume of an individual molecule of ideal gas is zero)
An individual molecule of ideal gas is assumed to have zero volume. The molecules of ideal gas are assumed to be dimensionless points...
I am not sure why it never occurred to me before despite actually having taken an advanced classical mechanics course in college, but how do we treat a collision where the objects involved are actually accelerating?
In the case where colliding objects move at constant velocity it is standard...
I have a question regarding the collision of two objects, specifically something heavy falling on something with a point. For example, if a 50lb ball of clay fell from 10 meters onto the point of a knife, would the knife's point have to withstand the entire force of the clay before the blade...
How to find the collision number if the moving bullet hits a few wooden blocks and every collision takes 10 percent of its speed. In which block will the bullet stay?
My apologies if the prefix is too high of complexity. I don't know where this would fall, difficulty or academically speaking.
While it may be surprising to some given Hollywood's portrayal of it in movies, if a person in wearing hard bulletproof armor is struck by a projectile, the person is...
Hello everyone, I have a doubt regarding the conservation of angular momentum.
When dealing with collisions between two objects, if the net external force is zero we know that the linear momentum is conserved; even when the system is not isolated, for instance because of gravity acting on the...
I spend a lot of time thinking about collision problems because for me they are both extremely interesting and often very difficult to grasp when one thinks about them beyond the basics we are taught in introductory or even intermediate university courses.
Suppose there is a perfectly elastic...
The speed of the block after the nth collision is
$$ V_n=(2e)^n*v_0 $$
By conservation of energy the block travels a distance $$V_n^2/(2ug)$$ on the nth bounce. So the total distance is
$$ d=1/(2ug)∗(v_0^2+(2ev_0)^2...) $$
$$ d=1/(2ug)∗(v_0^2/(1−4e^2)) $$
$$ d=1/(2ug)∗(v_0^2∗M^2/(M^2−4m^2))...
I've been working through Chapter 9 of Fundamentals of Physics (Center of Mass and Linear Momentum) and while I think I generally understand the different types of collisions, I notice that all of the problems state (or heavily imply) the type of collision after it has happened.
Does predicting...
In my textbook, it is stated that "if an object elastically hit an frictionless inclined surface with angle between the vector of initial velocity and an imaginary line that is perpendicular to the surface ##\alpha##,then the angle between the line and final velocity vector will also be...
Hi! Hope I'm posting this in the right place! I'm practicing for exams and came over this question:
A proton with mass ##m_p## is accelerated to a relativistic velocity, with kinetic energy ##K##. It collides completely inelastic with another proton, which has the same kinetic energy, ##K##...
My hypothesis:
A sequence with the gravitational waves detected, sent by modulating radio waves, could be received and used by other intelligent beings to find the corresponding sequence within their records and then compare it to calculate our spacetime position in relation to theirs.
As...
m1v1+m2v2=m1vs'+m2v2' , if car hits small fluffy object m2, initially v2=0, and v1'=v2' ... so
m1v1=[m1+m2](v2')
but why not energy? Why is there a KElost?
.5m1v1^2+.5m2v2^2=.5m1v1'^2+.5m2v'2^2 +KElost , and again v2=0, v1'=v2'
.5m1v1^2=.5[m1+m2]v2'^2+KElost
using consv of momentum...
So to cut to the chase, I missed my class' lesson on momentum - have tried to catch up, quite successfully but am baffled about this question. I know the conservation of momentum etc. but after trying for ages it's just not happening this question so any help would be much appreciated,
Oscar.
1. When an object attached to a fixed point with a string, is given a velocity and the string goes taut.
So it says in this book (Applied Mathematics 1 by L. Bostock and S. Chandler) that when the string goes taut, the component of the velocity of the particle becomes zero in the direction...
So, what I did was suppose the mass of ramp is $ M_r$ and let velocity at B of block be v, then, after inellastic collsion both bodies v' velocity
at B ,
$$M\vec{v}= M_r \vec{v'}+ M \vec{v'}$$
or,
$$ \frac{M}{M +M_r} \vec{v}= \vec{v'}$$
Now,
Suppose I take the limit as mass of ramp goes to...
After simplifying the equations, I got:
m1(v1-v1') = m2v2' (momentum) and
m1(v1-v1')(v1+v1') = m2v2'^2 (kinetic energy)
From there, I'm not sure what to do. I referred to a textbook and it said to divide the energy equation by the momentum equation (the simplified versions) and then do a...
Ignore the letter a. See b.
I disagree with the variation of the velocity. To me, that need to be 2(Vo+V)
" My point is that initial velocity before striking the wall was Vo towards the left and after the collision, the velocity is Vo + 2V towards the right, thus making the change of velocity...
Happy new year, I got very far in this question. I attempted to use conservation of energy first.
Ei=(Pfc)^2+mec^2 Where pf is the initial momentum of the photons
Ef=(γmec^2)+(pf'c)^2
Then used conservation of momentum
Pf=γmvcos(Θ)
Pf'=-γmvsin(Θ).
After that I added Pf and Pf'.
and used...
I tried solving it using this method and I got 12.5m/s, and assumed the collision was elastic.
The answer is actually 6.32m/s [41.5 degrees counterclockwise from the original direction of the first ball]; the collision is not elastic: Ek = 12.1J Ek`= 10.2J
I have absolutely no idea how the...
Homework Statement: Three particles A, B, and C, each of mass 𝑚, 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 speed 𝑢.
The masses of A, B, and C are now 𝑚, 2𝑚 and 3𝑚 respectively:
Again find the fraction of...
Alice and Bob are initially in the same inertial frame. There are 2 point test masses m1 and m2. Initially m1 is at the origin and m2 is on the positive x-axis. At time zero, m1 is instantaneously accelerated to velocity Vx in the positive x-direction. After some time, m1 collides with m2...
In short, I was trying to look into feasibility of deflecting an asteroid with a collision of ~32MJ of direct energy. I wanted to know how many collisions are necessary to deflect at a given time out (distance away.)
I found this link, where the collision is perpendicular to the motion of the...
I've come up with the following causes:
- air resistance
- parallax
- during the collision, some of the kinetic energy gets converted into thermal energy.
- invisible deformations
But I'm not sure which would be the biggest effect on the total momentum change.
Are there any other reasons that...
Part (iii) is the part I am stuck on and is a 5 mark question. I have some idea of how to attempt it shown below
momentum is conserved so mux = mvy + mvz
(where ux is the initial velocity before the collision of ball x, vy is the velocity after the collision of ball y and vz is the velocity...
Summary: The limitations of engagement and possible results of the Breit-Wheeler theory collider in relation.
*You will need to read the article for this to make sense Upon reading an article "Scientists discover how to turn light into matter after 80-year quest" I had a thought, How will...
Good Morning
May I ask about spatial collisions of bodies?
In undergraduate dynamics, we study that when two particles college, we have two final unknowns: the final velocity of each particle.
We first use the conservation of linear momentum.
However, we supplement the analysis with the...
No LHC this year (long shutdown), but Belle II at SuperKEKB started taking data a few days ago. Here is a press release.
Belle II started last year with a low luminosity (low collision rate) - still good for detector calibration and so on. The goal for this year is to increase the luminosity...
Hello! I am looking at the plot showing the ratio of cross sections of ##e^-e^+## to hadron, to ##e^-e^+## to ##\mu^+\mu^-##. Doing a first order approximation the data is in pretty good agreement (an error of about 10%). However when the first order correction to the QCD is added, coming from...
<< Mentor Note -- Poster has been reminded to use the Template when starting new schoolwork threads >>
Two particles of identical mass m interact with each other via central potential energy
Vcentral(r) = -V0(1-|r|/a), if 0 <= |r| <= a
0, if a < |r|
Constants are V0 > 0...
I have been searching for an answer to this for a really long time and I have not found any definitive answers as of yet. What I am trying to do is determine if and when two bodies collided between the times t0 and t1. Calculating this is much more straight forward if each body is only either...
The problem is given in David Morin's Classical mechanics.
Now, I jumped to solve part b of question. To find the number of bounces,we note that mass losses momentum of -2mV per bounce(This can be worked out from conservation of momentum and energy). Now initial momentum was MV. Then since per...
Homework Statement
My problem has two parts.
1) We have two point masses ##m,M##. and there is another mass ##m_1## between them.They are all aligned in a line. Mass ##M## is moving with speed ##u_1## toward ##m_1## and after collision and all other masses are not moving. we want to find...
Homework Statement
The problem is from the Monbukagakusho exam.[/B]
An object of mass M is hanging by a light spring of force constant k from the ceiling. A small ball of mass m which moves vertically upward collides with the object. After the collision, the object and the small ball stick...
Hi, this is just a question I've had for years and have not been able to figure out because of conflicting information. I have read that space is expanding and that it's speeding up, but also have heard that in about 5 billion years our galaxy and Andromeda will collide. How is this possible...
Homework Statement
Dear colleagues, my problem is following:
The ball of mass with the initial velocity collides with a system of two identical balls of mass each, connected by a massless hookean spring with stiffness and length .
It is necessary to find the final velocities of the...
I need help, I've been staring at this problem for over an hour and trying to find similar problems online with no luck.
A 65 kg person is skiing down a hill. The skier's speed at the bottom is 15 m/s. If the skier hits a snowdrift and stops in .30s A)how far does the skier go into the drift...
If I fire an electron and positron bunch both in the same direction away from my experimental accelerator rest frame such that the electron bunch is fired with higher energy towards a "read end" collision with an already fired positron bunch and they collide a short distance away from the...