Interaction between two or more bodies that results in physical contact and an exchange of momentum between the bodies involved.

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0answers
17 views

Photoelectric effect - elastic collision [on hold]

In an elastic collision, since the electron leaves with the same amount of energy as it originally had, does that mean the photon receives no energy? Does this even result in a photon emission, if so, ...
29
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6answers
4k views

Newton's 3rd law… hitting drywall (which I break) vs hitting a brick (which breaks me)?

According to the Third Newton's law of motion: For every action there is an equal and opposite reaction. So, I understand that if I hit a brick wall with $50\, \mathrm{lbs}$ of force, the ...
5
votes
3answers
90 views

What causes more damage, a head-on car crash at 30km/h or one car at 60km/h crashing into a stationary one?

Which will cause a greater impact? Two identical cars colliding head on (in opposite directions), each going at $30\;\mathrm{km/h}$ OR One car travelling at $60\;\mathrm{km/h}$ colliding into a ...
2
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1answer
34 views

Extinction level meteor effects on Earth's crust pending on the surface area upon impact

Would it be possible to have a extinction level meteor hit Earth depending on shape to actually create minimal damage if turned on its thinnest area rather than hitting flat? The meteor would enter ...
1
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2answers
60 views

Question regarding elastic collisions and the conservation of momentum / energy [on hold]

I've been working on this question for a few hours and I cannot quite convince myself that my answer is correct. I've read the relevant section in my textbook, but I guess the lightbulb just isn't ...
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1answer
42 views

Does the shape of a meteor make any difference during an impact? [on hold]

Would the shape of the meteor make a difference on the impact? Like a Olympic diver would a spear shaped meteor make less damage to the surface of the Earth while creating more magma movement rather ...
-3
votes
1answer
94 views

Could a meteor cause the flood from Noah's time in the bible? [on hold]

In the Bible it was said before Noah's flood man lived to be around a thousand years old. Shortly after the flood the life span went to about 120 years. Today 80 years. Could a meteor have hit at ...
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0answers
11 views

Determining velocity and angular velocity after a collision between two 2D rectangles [on hold]

Say I have two rectangles, which each have four vectors (which represent their vertices), a velocity, a mass, an angular velocity and a rotation (which is only used to simplify calculations as I don't ...
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2answers
45 views

When do two point masses orbit or collide? [closed]

Suppose we have a universe containing two point particles with possibly different masses and initial positions/velocities (with respect to some fixed reference frame). Neglecting relativity and ...
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1answer
46 views

In the following problem, where did $v_{cm}$ come from? [closed]

In the following problem, where did come from? I don't recall any formula that this equation could be derived from...?
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3answers
43 views

Where did 2mv come from in the solution to the question below?

I know that this is an inelastic collission, which is why the two objects have the same final velocity. However, I don't understand why they equated the V1(M+m) to 2mv. Where did they get 2mv from?
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votes
1answer
73 views

What happens in this collision? [closed]

First, I describe a simple contraption. Second, I describe a simple collision. Third, I replace a box in the collision with the contraption and ask whether, "What happens after the collision?"-i.e., "...
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votes
1answer
36 views

Is it possible for an asteroid to shoot through the earth like a bullet?

Is it possible for an asteroid to shoot through a planet like a bullet ? If so how much force would be necessary for it too go through and out the other side . Using the earth diameter as a base ...
0
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2answers
60 views

Impulse in perfectly elastic collision

I am implementing this simplified model at the moment, and I am trying to get my head around the physics concepts behind this model. Event-Driven Simulation So the model has two parts, first is ...
1
vote
1answer
51 views

Two carts on a frictionless rail collide [closed]

There're 2 carts on a frictionless rail. Their masses are $4m$ and $2m$. (The carts are on the rail in this order). The first cart has a velocity of $v_1$. The first cart hits the second. Knowing that ...
2
votes
1answer
48 views

Collision/Crumpling problem possible solution mistake

This question is from Physics for scientist and engineers , Ohanian . Two automobiles of 540 and 1400 kg collide head-on while moving at 80 kmh in opposite directions. After the collision the ...
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2answers
57 views

Finding if two objects collide

The question that I'm trying to understand is this: This is the part of the solution I don't understand: From my knowledge, if $v_p-v_q$ is due south, this means $r_p-r_q$ is also due south, ...
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1answer
50 views

Impulse of two different objects

I was running over a question, A collision occurs between particles A and B which are moving in opposite directions in the same straight line. The impulse on each particle in the collision is 2N.s, ...
3
votes
1answer
61 views

Collision between a “spring” and a particle

I am currently attempting to create a simple 2D physics engine, and I just need to know how to solve a certain collision. I have particles, and between any two particles, springs can be connected. ...
2
votes
2answers
97 views

Newton's Cradle: why does it stay symmetric? [duplicate]

How is it that always the same number of balls leave at the other end in Newton's cradle. I understand that the momentum needs to be conserved, but as momentum is defined as p=m*v couldn't you have a ...
1
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0answers
26 views

The geometrical-locus result of collision and fall

A classical momentum-conservation experiment follows about this way: On a table there is a sloped track and a ball is rolled down. At the bottom of the track, a second ball is at rest. The balls ...
0
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2answers
67 views

Simple mathematical model for a bouncing ball

I started coding a physics program that simulates gravity - specifically a bouncing ball - and I've already learned a lot researching the topic but the bounce still doesn't look quite right. I need a ...
2
votes
1answer
47 views

How can you find the impact necessary to change the direction of Earth's spin?

If an object the mass of the moon was to hit earth's surface at an angle that would be in the opposite direction of earth's spin, how can you find how much momentum the object needs to cause earth to ...
3
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2answers
58 views

$e^+e^-\to q\bar{q}$: Reconstructing $q\bar{q}$ energy and momentum

Question In a real collider experiment e.g. LHC / LEP how can one reconstruct the energy and momentum of the resultant $q\bar{q}$ pair produced from the process $e^+e^-\to q\bar{q}$? Specifically, ...
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1answer
41 views

Intuitive picture for Mandelstam $t$

In tree-level electron-positron scattering one has two possible channels corresponding to Mandelstam variables $s$ and $t$. The $s$-channel ist fine, there $\sqrt s$ is just the center of mass energy ...
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1answer
39 views

Perfectly elastic and inelastic collision of photon

I`m having some trouble understanding (and finding any relevant information) about the elastic and inelastic collision between a photon and a mirror in non-quantum machanical terms. When a photon hits ...
0
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0answers
7 views

Head-on collision near lightspead [duplicate]

Assume two objects moving near light-speed (for this experiment let's say $0.9c$) towards each other. The speed is measured from an observation platform at the collision point (as I understood ...
1
vote
1answer
80 views

Why a bullet leaves a hole on glass where stone makes scratch?

When we throw a stone it breaks the glass with scratches. But when a bullet hits the glass it leaves a small hole(not always) . I want to know the specific reason behind making hole and scratch.
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0answers
14 views

Simple deduction of differential cross section from total cross section

In Povh's book "Particles and Nuclei" we read the following: I simply cannot wrap my head around what happened from eq. 5.20 to 5.22. How did he deduce that the cross section for the scattering into ...
0
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1answer
65 views

How do you determine which way two objects will travel after collision when given their respective masses and speeds?

I was practicing some Mechanics, and I came across a problem that involved an impact between two objects: I understand how to approach the question: Apply the conservation of momentum, and use the ...
-1
votes
3answers
58 views

Change in linear momentum [closed]

Let A and B be to rigid blocks. A is stationary while B is moving with a velocity $u$. So if B collides with A. (These blocks are on a frictionless surface.) What would happen after B collides with ...
0
votes
4answers
137 views

Why don't two objects move with the same velocity after collision?

I have a problem with understanding the nature of collisions and their outcomes. From my understanding, I come to think that when a mass collides with another, both of them should always have equal ...
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0answers
39 views

Colliding beams vs static target

In this problem I need to find the threshold energy of a positron-electron collision that creates a Z boson (the reverse of the following picture; Z mass 92 GeV) in two distinct cases: collision ring ...
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1answer
39 views

Momentum equation of a beam hitting a stationary target to create antiprotons

I'm struggling with the solution of a physics exercise which is to calculate the minimum energy needed to create antiprotons when a proton beam scatters on a stationary proton target: $$p + p \...
0
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0answers
16 views

Momentum conservation problem, elastic collision [duplicate]

This question has got me thinking for a while now and I haven't been able to come up with any answer at all. I've done the basic conservation of momentum, kinetic energy but I have no idea how to ...
1
vote
1answer
44 views

Variation of Veritasium bullet block experiment

I'm new here. this is in reference to the video posted by veritasium on the bullet block experiment. i realise there is already a thread on this but i want to ask a variation of the question. so ...
0
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1answer
88 views

What is the best way to calculate impact time with collisions?

I've been teaching myself physics and I've been wondering about the impact time in collision calculations. The scenario I've been using to learn is an object with a mass of 4000 kilograms colliding ...
0
votes
1answer
46 views

Difference between sudden force and impulsive force? [duplicate]

What is the difference between a sudden force which continues to act on the body, and an impulsive force? What would be respective speeds of the body just after time= 0?
-1
votes
1answer
50 views

The ratio of masses in an elastic collision [closed]

Two blocks of mass $M_1$ and $M_2$ moving along a 1-dimensional straight line with velocities $V_1$ and $V_2$, respectively, collide elastically. After the collision they move with respective ...
0
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1answer
29 views

When to consider friction as an impulsive force?

Suppose a ball obliquely strikes a rough horizontal surface then it experiences a frictional impulse and conservation of linear momentum cannot be done on the horizontal direction. Now consider ...
0
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1answer
83 views

Collision with a stationary Hydrogen atom [closed]

Can some explain me what happens when an electron or neutron collides with stationary Hydrogen atom? What are conditions for elastic and inelastic condition? For example, how to tackle following ...
1
vote
1answer
31 views

Using the central equation for inelastic collisions entropy change

I have what appears to be a simple question but I seem to be missing something. Take a constant temperature system where a ball travelling at $5ms^{-1}$ strikes a stationary ball and sticks to it in ...
1
vote
1answer
36 views

How do these particles sort themselves by size? [duplicate]

I have this bowl of sodium polyacrylate (Insta-Snow) that has been drying out for a few weeks. At this point it consists of solid pieces ranging in size from 3 or 4 mm across to much smaller ones ...
0
votes
1answer
19 views

Spheres collide with merry-go-round [closed]

Four spheres, with uniform densities $\rho_1, \rho_2, \rho_3, \rho_4$ and radii $r_1, r_2, r_3, r_4$, respectively, roll without slipping with constant velocities $v_1, v_2, v_3, v_4$ along tracks ...
0
votes
1answer
20 views

Physics of Auto Crashes and Airbag Modules

I recently saw a post (that was pretty old) asking why we don't consider the jerk function more often in sciences that deal with impacts or sudden accelerations. The general belief was that impacts, ...
3
votes
2answers
67 views

Does inelastic collision say the ball bounces back to you when thrown at an angle on ground?

I created a bounce simulation using exactly the formula from Wikipedia. The behavior I observe is not what I would expect in two cases: When two balls hit off-centre, they act the same as if the ...
0
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1answer
35 views

How do black holes join each other? [duplicate]

If black holes can swallow any object, and can radiate energy, then how could black holes join each other and can form bigger black holes?
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2answers
97 views

How can work be done during collisions? [closed]

Consider a collision between two material points, 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 ...
3
votes
3answers
111 views

Car Crash Question… (Conservation of Momentum?) [duplicate]

Dumb car crash question. I think this is a conservation of momentum problem. In one scenario, two 4000 lb cars (car A and car B) each traveling at exactly 35 MPH in opposite directions have a ...
0
votes
1answer
85 views

Technique to Solve 2-Dimensional Linear Momentum Problem

Problem: After a completely inelastic collision, two objects of the same mass and initial speed stick together and move away at half their initial speed. Find the angle between their initial ...