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

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What makes a collision superelastic?

I've seen an online definition: A collision in which potential energy is converted into kinetic energy so that the total kinetic energy of the colliding objects is greater after the collision than ...
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1answer
110 views

Can we generate electric current by injecting electrons into a copper panel

Suppose I take a vacuum tube and accelerate electrons in it by electric fields then collide it on a copper plate. Will the electrons then go inside it and generate an electric current by putting a ...
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3answers
2k views

The momentum of a swinging sword

Suppose you are faced with a zombie, and the only way to kill it and save yourself is to chop its head off with your sword. However, you are very weak from illness, and can only afford to strike once. ...
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1answer
264 views

Calculation of velocity via kinetic energy and momentum yielding different answer

I am attacking the given problem (as a preface I'm not asking to be spoon fed any answers, just looking for clarity from people much smarter than myself) A 15.0kg block is attached to a very light ...
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0answers
70 views

During perfectly elastic collision of two objects $A$ and $B$, how much is the initial speed of object $A$ affecting the force applied to $A$ itself?

I got stuck in what seemed to be an easy problem. If two bodies $A$ and $B$ collide perfectly elastically and head-on what is the equation that gives us the forces applied to $A$ and $B$, given a ...
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2answers
231 views

Why is momentum conserved in inelastic collisions? How is it related to momentum-impulse theory?

First of all I want to mention, that I've found many questions around this site and in other websites dealing with my question; however, I don't think they answer my question fully. So I am here to ...
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1answer
126 views

Dissipated Energy from Falling Object using Lagrangian [closed]

A plate of mass $M$ moves horizontally with initial speed $v$ on a frictionless table. An object of mass $m$ is dropped vertically onto it from the height $h$ and smashes. How much energy is ...
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2answers
258 views

Case of the mysterious bullets (taken from Mad About Physics)

"Two ideal bullets, identical in shape, size and mass, strike the same target with the same speed just before the collision. Force meters at the target register two times the force value for bullet A ...
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1answer
162 views

Linear Momentum Based Problem [closed]

A ball moving along a straight line collides elastically with another stationary ball of the same mass. At the moment of collision the angle between the straight line passing through the centres of ...
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1answer
103 views

Relating to Inelastic Collisions

There is a very simple equation for an inelastic collision but it really only applies to 2d scenarios: $$v = \frac{(m_1 u_1 + m_2 u_2)}{(m_1+m_2)}$$ What would be the equation for an inelastic ...
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1answer
965 views

Mars just collided with Earth! A question of eccentricity

One of the standard theories behind the formation of our Moon is the giant impact hypothesis, according to which Earth was struck by a Mars-sized body (about $10\%$ the mass of Earth) early in its ...
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2answers
264 views

Reflection - reaction force direction

Let's say an object hits a wall. When the object is reflected does the direction of the reaction force caused on the wall look like the red arrow? Does that direction depend on how "strong" object is ...
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2answers
601 views

Conservation of Momentum: Perfectly Elastic Collision, Example Problem

I am a middle school science teacher. I'm a little rusty on my physics knowledge, and I came across a question that I feel like I should be able to solve, but it also feels like there is a piece of ...
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2answers
227 views

How do we prove that the initial velocity is equal to final velocity relative to centre of mass?

In elastic collision it is stated that the initial velocity relative to centre of mass is equivalent to final velocity of centre of mass of the same object. How do we prove that?
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3answers
402 views

Object falls and hits ground - which forces are involved to change its momentum?

When an object falls and hits the ground - which forces are involved to change its momentum? Should $m\vec{g}$ be taken into account of the forces that were involved in the change of momentum?
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0answers
126 views

What is the relationship between the Young's modulus of a material and the elasticity of a free fall collision

I'm coding a 2D physics simulator based around the Newtonian physics principles with some alterations due to computation limits and I am at the stage of creating a collision event between a planetary ...
112
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3answers
30k views

Why doesn't matter pass through other matter if atoms are 99.999% empty space?

The ghostly passage of one body through another is obviously out of the question if the continuum assumption were valid, but we know that at the micro, nano, pico levels (and beyond) this is not even ...
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1answer
297 views

How can one calculate the gamma-ray energy spectrum for proton-proton collisions?

How does one calculate the the energy spectrum of gamma-rays produced by a proton-proton collision? I'm at a complete loss.
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1answer
810 views

Elastic Collisions and Relative Velocities

In a 1D elastic collision, it is well-known that the relative velocities of the two objects (before and after the collision) are reversed. What is the extension of this result to 2D or higher? Is ...
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2answers
314 views

Is momentum conserved in the collision of a ball with a hanging rod?

Suppose we have a situation like A ball of some mass $m$ with some velocity collides with rod hinged at point $A$. Is momentum conserved in this situation? I know that hinge will give impulsive ...
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1answer
136 views

How to calculate the deceleration of two trains moving with the same velocity? [closed]

Two trains travelling on the same track are approaching each other with equal speeds of 40m/s. The drivers of the train begin to decelerate simultaneously when they are just 2km apart. If the ...
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1answer
39 views

Definition of a symbol $s_{NN}$ appearing in particle physics

What is the meaning of $s_{NN}$ in particle physics? See e.g. here http://www4.rcf.bnl.gov/brahms/WWW/thesis/karabowicz_phd_thesis.pdf page 18 in the pdf. What is its relation to energy? I ...
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3answers
25k views

Small car colliding with large truck

A small car collides with a large truck. Why do both vehicles experience the same magnitude of force? Wouldn't the large vehicle experience less force than the small one?
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2answers
558 views

Hockey puck collision [closed]

I have a homework question in which a sticky hockey puck traveling at constant velocity parallel to the side of the rink strikes a stationary puck and sticks to it. The angels between centres at ...
2
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2answers
521 views

Elastic collisions and conservation of momentum

If you have an elastic collision between objects 1 and 2 and where 'kinetic energy is conserved', does this mean object 1 will always have the same velocity it had before the collision? Or will ...
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0answers
283 views

Modelling an Inelastic Collision

I've attempted to model the inelastic collision between a moving mass and a large stationary object, e.g. dropping an ball on the floor, for analysing the approximate kinematics and heat dissipation ...
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0answers
340 views

Two cars colliding with different speeds

If I have one car travelling at 30 m/s and another travelling at 10 m/s both weighing the same amount, why is it that the car travelling 10 m/s would have more damage? According to Newton's third law ...
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1answer
117 views

Collisions of celestial objects

When massive, spherical celestial objects collide, how long does it take for the objects to coalesce into a new, larger, spherical entity under the influence of gravity? Examples of the above:- ...
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1answer
40 views

A particle collides with another particle in an (infinitesimally long?) elastic collision, what is the resultant force?

When an object collides with another object in an elastic collision, the first object exerts a force on the second object (and vice versa); how do you calculate the force that the object experiences? ...
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8answers
1k views

Physics Paradox about Newtons Second Law $F=ma$

If force equals mass times acceleration, wouldn't a basketball dropped from the top of the Eiffel tower exert the same force on the ground as a basketball dropped a foot off the ground? They both ...
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2answers
287 views

Is it possible to determine the outcome of any impact knowing only the ratio of masses? [duplicate]

In elastic collisions in 2-D if two balls $A$, $B$ ($m_A = m_B$, $R = 1$) have equal mass we can determine in advance the outcome of the collision. If cue-ball $A$ impacts object-ball $B$ (at rest) ...
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2answers
8k views

What are all the equations we use to calculate how bounces work?

I mean, what is the object's final displacement, or the function that describes the object's height over time (see [1]) of an object thrown by a height $h$ with a speed of $\vec{v_0}$, a mass of $m$, ...
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0answers
313 views

Experiment to verify a spring constant

In my high school physics class, I had students do a Hooke's Law lab to measure an unknown spring constant. Once we compared everyone's data we came up with a class value for $k$ of 253 N/m. We then ...
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0answers
234 views

Trying to make a realistic simulation of 'breaks' (Pool)

I'm working on a 2D pool simulation project right now, and I'm trying to create good looking physics that are also performant. After collisions are detected, I update the velocities of the balls. So ...
2
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3answers
389 views

Angular Velocity after a frictional impulse [duplicate]

I am modelling 2D physics collision into simulations. In Physics for Game Programmers, Grant Palmer book, the velocity Vn1 after collision is mentioned to be independent of the friction coeff. ...
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1answer
69 views

Will the bouncing particle exert greater force on the surface?

Imagine elastic collision and no energy is lost from the system. A particle is emitted from the bottom of a box. The box is in inertial motion. The particle hits the top of the box and travels in ...
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2answers
480 views

Question about impulse and momentum

Check this question first please My question is: Why can't I use equations of motion to get the final speed after rebounding?Acceleration not equal to $9.8 \text{m/s}^2$ or the intial after ...
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3answers
360 views

Does the stationary object deform more than the moving one after a collision?

Given two identical clay disks on an air track, one is stationary and another is moving at "high" speed. After colliding, does the stationary disk deform more than the moving one? If it matters, the ...
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2answers
5k views

Can a bullet shot through a glass make a clean hole?

One can often see (hopefully only in the movies) that a bullet shot through a pane of window glass leaves a hole in it, but overall the glass is left largely intact. However, a low-speed projectile, ...
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0answers
68 views

Can a projectile moving at supersonic velocities leave a silhouette in whatever it hits?

I was recently reading this, and Floris's answer confirmed my knowledge that the information of an collision travels at the speed of sound. While I was thinking about that, my mind wandered and I ...
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3answers
335 views

When we catch a falling object, where does its kinetic energy go? [duplicate]

Some of it is transformed into heat and noise, but where does the rest go? Further details: The object does not bounce off (e.g. a sack of rice marble ball). The hand remains completely static ...
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2answers
299 views

What indicates if an object will bounce back?

If I throw a small rock (m = 1kg) at a big rock (100kg) the small rock rebounds. Let's say my weight is 80kg, if I would jump into a big rock instead of bouncing back I would move in the same ...
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2answers
396 views

Force of a Train

Imagine that there are two trains and the first train is twice as long as the second train. They have the same mass per unit length and they are traveling at exactly the same speed. If the first ...
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1answer
43 views

Can the speed of a vehicle be determined based upon the extent of injuries to a pedestrian?

While driving at night in a Prius, at varying speeds of 5-20 MPH in heavy, stop-and-go traffic on a 4 lane city street, two pedestrians in dark clothing were struck (not in a crosswalk). One died of ...
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1answer
171 views

Prove the relation between relative velocity ,momentum and energy

In Chapter 8 of F.Mandl's book Quantum field theory, during the derivation of the differential cross section, the following relation is used: $$E_1E_2v_{rel}=\sqrt{(p_1p_2)^2-m_1^2m_2^2} \,\, ,$$ ...
4
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2answers
862 views

Does a force really act on a body during a collision?

Consider two bodies A(black) and B(red) having equal mass. A is moving at a constant speed towards B, which is stationary. At certain point of time, they collide elastically, $\therefore u_{A}=v_{B}$ ...
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97 views

Domain of different types of collision?

Can anyone tell me why elastic collision occur between atomic particles? inelastic collision occur between ordinary objects? perfectly inelastic collision occur during shooting? ...
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3answers
81 views

Why doesn't an object that collides with one that is at rest just do a 180?

Newton's third law says "for every action, there's an equal and opposite reaction." So why is it, say, that when a pool/billiards ball hits the wall of the table, the ball doesn't just turn around?
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2answers
247 views

Playing catch in space?

I was thinking about this on the bus (exam this week :P). What would happen if two people played catch in outer space? Lets say person A and B are in space at rest, A throws a mass m at B, what ...
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7answers
3k views

Ball flying towards me or me flying towards ball

Suppose a ball is flying towards me at a speed of 10m/s and that, on impact, I feel "x" amount of pain. If, instead, it was me flying towards the ball at the same speed, with all other conditions ...