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.
Suppose a bar is fixed to an axle at one one so that it can pivot. The bar is initially motionless, but is set rotating about it's axle when impacted by a ball. (The ball does not strike the bar at it's pivot point.) Suppose the collision is such that the bar is set rotating and the ball is...
Parallel:
M1V1+M2v2=M1V1’+M2V2’
(0.5)(3)+0=(0.5)(cos60)(3)+V2’Cos(x)(0.5)
V2’cos(x)=
Perpendicular:
M1V1+M2v2=M1V1’+M2V2’
0=(0.5)(0.3)(sin60)+V2’sin(x)(0.5)
V2’sin(x)=
And the divide 2 by 1
Which is tan(x)=2/1
And then plug then back into solve, but I don’t think we do it like this because...
Hi
I've tried solving this question but it seems that I flipped the direction of the impulse, what did I interpret wrong? the question didn't give any clue on their direction before so I couldn't infer the direction of the impulse. It also just gave me the magnitude without the direction. I...
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...
Hi again.
Is it plausible that an ice giant like Neptune could be shattered by a collision such that it keeps a tight debris field for a few hundred thousand years before recoalescing as a planet?
In my story the characters hide in a debris field and refine the ices for fuel.
Also, if the...
I started by writing the equation v1i + v1f = 2v and then drawing a triangle with v1i, v1f, and 2v as the three sides. Then I used the Law of Cosines to solve for cos theta but this did not lead to a solution. Could I have a hint on how to begin? Thank you!
Hello to everyone, first of all shame on me I has to ask and can not figure out it by myself...
The problem is I am trying to code game where two homogenous discs with same mass and same diameter, no fricition due to gravitational forces, can collide.
I can figure out the speed and direction...
I'm writing a paper on the movie realism of the A-team movie. The basic situation is that the guys are falling inside a tank with terminal velocity into a lake. I'm stumped on how to calculate the force that is created on impact, though I imagined it being done with some kind of pulse equation...
https://futurism.com/why-you-can-never-actually-touch-anything/amp
We know the friction happens because of the intermolecular forces between the atoms of the surfaces in contact. When we place something on other there are places where they get come in contact there are bonding formed and due to...
We know that the Ug is converted to KE and Us. I thought that since the system loses energy after the collision that we shouldn't use the equation hnew= delta x + h.
I thought instead that maybe the h we should use is xmax, because that's when there is maximum Ug and there is no other energy...
Well, not right away. It's about 10 000yrs in the future.
From: THE ASTROPHYSICAL JOURNAL LETTERS
The Unanticipated Phenomenology of the Blazar PKS 2131–021: A Unique Supermassive Black Hole Binary Candidate
Popular version...
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...
two moving and rotating, uniformly weighted disks perfectly inelastic collide. The disks are rotating in opposite directions (see the diagram) At the moment of their collision, the angles between their velocity and the line connecting their centers are 45 degrees. The velocities are therefore in...
figure 11.12
I need someone to explain why the angular momentum of the ball is ## L_{f} = -rm_{d}V_{df} + I\omega## rather than ## L_{f} = rm_{d}V_{df} + I\omega ##. How to distinguish the sign of the angular momentum?p.s. ##\Delta\vec{L}_{total} = \vec{L}_{f} - \vec{L}_{i} = (-rm_{d}v_{df} +...
I was able to solve for the velocity of MB and got my answer as 4.47m/s.
The main issue right now for me is how to get the angles. I'm really confused on what most people have been posting as we didn't get a groundwork on this topic and so most of the basics I had them self taught.
So far I...
I'm trying to understand Newton's third law in the context of collisions. Assume that one body has mass M kg and is traveling in the positive x direction with acceleration A m/s^2. Assume that the second body has mass m kg and is traveling in the negative x direction with acceleration a m/s^2...
Standard formula for final velocities ##v_1##, ##v_2## in elastic collision with masses ##m_1##, ##m_2## and initial velocities ##u_1##, ##u_2## is given by $$v_1 = \frac{m_1-m_2}{m_1+m_2}u_1+\frac{2m_2}{m_1+m_2}u_2$$$$v_2 = \frac{2m_1}{m_1+m_2}u_1+\frac{m_2-m_1}{m_1+m_2}u_2$$.
By rearranging...
1 = elephant
2 = fly
So I am trying to find v'2 which is the final velocity of the fly. I have v1 the initial velocity of the elephant 2.1m/s. So I plug it into the equation and have v'2=(2m1/(m1+m2))*2.1m/s. We are not given the masses so I just know m1>m2 but I don't understand how that will...
Drawing:
I decided to attempt to approach this as several collisions. So we can start with this:
Object 1-Object 2
This collision is elastic, so we know that ##P_i = P_f##. We also know ##K_i = K_f##.
So,
$$mv_{1i} = mv_{1f} + mv{2_f}$$
$$1 = v_{1f} + v_{2f}$$
$$v_{2f} = 1 - v_{1f}$$
and...
I am stuck. Please ignore my handwriting. I am working on latex.
All I am taking is x and y coordinates same of both particles.
Yes they will meet at some time t.
As seen in the summary, my question is purely hypothetical and I understand that it would most likely be impossible to happen (or I just haven't read enough). The concept that quarks and leptons are the fundamental particles of the universe has existed for a while now - therefore we know that...
I attempted to do mvf-mvi to find the impulse, but had trouble figuring out what to use as v (where does the angle of 3degrees come in?), and thought that there had to be more to the problem considering the other details I was given. I then attempted to maybe calculate the kinetic energy lost...
I am trying to code collision of two objects. When they collide, instead of rebound or motion of them according to their velocity, i want them to stick together and move in direction of resultant normal velocity. It is not plastic collision. I want a force that stops the rebound. how can i...
I don't really understand the question. A proton collides obliquely with another proton means that the first proton moves at certain angle with respect to horizontal?
This is my sketch:
Is that correct? If yes, is it solvable since there are so many unknowns?
Thanks
My approach so far is to use F = ma.
The forces acting on the block in the horizonital direction are friction and the force of the spring. Choosing the direction towards the spring as the positive axis.
Therefore: F = ma
-Fr - kx = ma
Solving for a = (-Fr - kx)/m
If I plug in values I end up...
This is the problem statement from the textbook.
“A ball with an initial speed of 10.0 m/s collides elastically with two identical balls whose centers are on a line perpendicular to the initial velocity and that are initally in contact with each other (Fig. 6-33). The first ball is aimed...
Hi ! My question is the following:
If there is a redshift in astronomical observations with other galaxies, as our Milky Way galaxy is approaching with the Andromeda galaxy, they must surely be in an accelerated approach due to the force of gravity between the two galaxies, and as our galaxy...
In a head-on collision between the proton and electron, what is the squared 4-momentum transfer between the two particles.
Starting with the difference in momentum of the electron with the 4-vectors before and after the event: $$(P-P')^2=P^2+P'^2-2P\cdot P'$$
The circumstances are such that the...
(a) ##u_{min}=\big(1+\frac{m_2}{m_1}\big)\sqrt{2\mu_k g d}##
(b) ##x_f=\sqrt{\frac{2h}{g}\Big(\big(\frac{m_1}{m_1+m_2}u\big)^2-2\mu_k g d\Big)}##
Can someone check please?
Now, deriving relativistic momentum isn't terribly difficult, but that's not the same as understanding it. I'm trying to figure out why conservation of momentum in special relativity requires the gamma factor.
When I looked at conservation of momentum in elementary physics, we basically just...
I am just wondering how best to visualise a Compton scattering event. Since a photon has no mass, we can't exactly presume it's the same as two masses colliding even if at relativistic speeds.
Does the photon encounter some kind of force field as it approaches the stationary electron ? If so...
Ball A of mass 2kg, is moving in a straight line at 5 m/s. Ball B of mass 4kg is moving in the same straight line at 2 m/s. Ball B is traveling directly towards Ball A. The balls hit each other and after the impact each ball has reversed its direction of travel. The kinetic energy lost in the...
Consider an observer on Earth (Neglect any effect of gravity). Call him A. Let 2 rockets be moving in opposite direction along x-axis (x-axis coincides with the x-axis of A) with uniform velocities. Call them B and C. At t=0, in A's frame, the rockets are separated by length ##l## . Let ##V_a##...
Let's assume I have a ball moving at a constant velocity and it collides with a spring and the spring compresses n cm. If I know how much mass the ball has and the spring constant D, how would I calculate the Force? I mean since F = dp/dt I would have to know the time in which the stopping...
Problem : The statement is given above. Here I attach the image of the problem to the right.
Attempt :
(1) Condition for collision : For the two particles to collide, there should be no relative velocity perpendicular to their "separation vector" ##\boldsymbol{s}##. Hence, we must have ...
Solutions are given in the book, but I could not understand some part of them.
For problem 2.2, denote the 4-momentum of the photon by ##\mathbf P_\gamma##, that of the particle by ##\mathbf P## and the values after scattering by primes.
Then by the conservation of momentum, we have ##...
See working attached.
My problem is that I have come up with 3 equations but 4 unknowns (mq, up, vp, vq). Is this problem solvable?
The answers say:
a) 0.5 m/s b) 0.65 m/s and c) 0.34 m/s
Many thanks
Hi, I'm studying how distance affects the impact of magnet collision. Would like to have some idea before conducting experiment.
Imagine
1. holding a magnet at different distance near a fixed metal
2. release the magnet; the magnet attract and collide to the fixed metal
Will the distance affect...
For car 1, the parametric equations are x = 1 + 0.8t and y=t. For car 2, the parametric equations are x=0.6s and y=2+s. (Let t and s represent time). Solving the system of equations, when the x values are equated are the y values are equated, I get s = -13 and t = -11. I assume that the 2 cars...
2 balls (Ball 1 and Ball 2) collide fully elastically and their relative velocity stays the same as but in sign opposite to that before the collision. Is there any sort of reference frame in which Ball 2 is always fixed (at rest) so that one can look at their relative velocity always in that...
Consider the system of the mass and uniform disc.
Since no external forces act on the system, the angular momentum will be conserved. For elastic collision, the kinetic energy of the system stays constant.Measuring angular momentum from the hinge:
##\vec L_i = Rmv_0 \space\hat i + I \omega_0...
[Mentor Note: thread split off from a different thread]
https://www.physicsforums.com/threads/heavier-objects-fall-faster.1002022/
Since seeing this thread yesterday, I have been trying to derive the time equation for the collision of two masses due to Newtonian gravity. Unfortunately, this...
https://www.plasmaphysics.org.uk/collision2d.htm
This is the only one I found, but when I plug in the numbers of his example I get a wrong result. Do you know any others who solved it i.e. considering the angle of impact? Angle of impact I name the angle that is shaped between the initial dx...
The way I learned to solve this was to switch to a frame of reference where one object is stationary.
given: m1 =0.6kg v1 = 5.0m/s [W], m2 = 0.8kg v2 = 2.0 m/s [E]
Setting v2 to rest by adding 2.0 m/s W to each object
New velocities are v1 = 7.0 m/s [E] and v2 = 0.0m/s
Then using the...