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

learn more… | top users | synonyms

2
votes
1answer
41 views

Ball Bounce Acceleration at the Point of Bounce [closed]

simple question but I wanted to confirm my approach of thinking about the problem. Question: A rubber ball is dropped from the fifth story of a building and free falls to the ground, after which ...
5
votes
1answer
99 views

Why doesn't the 9th ball move in the break in the nine-ball pool game?

In the game of nine-ball pool, we break the rack like shown below: In the break, we hit the 1st ball with the cue ball. Many people familiar with pool games say that if the rack is constructed ...
1
vote
2answers
150 views

Where does the energy go if a ball hits the ground WITHOUT bouncing? [duplicate]

so if a very un-bouncy object hits the floor and crashes into it rather than bouncing, where does most of the energy go? Does it simply turn into heat from friction? Or does it go into the Earth's ...
-1
votes
2answers
84 views

Will I die from a 50-foot fall? [closed]

Sorry if I didn't ask this in the right place, but... Will I die from a 50-foot fall? What are the chances of survival? I know this is more of a biology question or something, sorry :(
0
votes
1answer
50 views

Acceleration of bodies

Whenever when there is collision or when there is continued movement during contact we assume there is only continued acceleration and no other type of motion. We use this assumption to find various ...
0
votes
2answers
23k views

Calculating force of impact

Since $\text{force = mass}\times\text{acceleration}$, is it right to say that an object traveling at a high constant velocity (zero acceleration), exerts zero force upon impact with a stationary ...
2
votes
3answers
3k views

Conservation of 4-momentum in special relativity

I understand that the inner product of two 4-vectors is conserved under the Lorentz transformations, so that the absolute value of the four momentum is the same in any reference frame. This is what I ...
0
votes
1answer
401 views

Finding the total energy in centre of mass frame

I'm working through a problem in a special relativity textbook (Woodhouse) and I'm having some difficulty. I have to show that if I have a particle of rest mass $M$, total energy $E$ colliding with a ...
5
votes
0answers
514 views

Hamiltonian function for classical hard-sphere elastic collision

I'm trying to find the Hamiltonian function for a system consisting of a single particle in one dimension colliding elastically with a wall at $x = 0$. Everything I've read on the topic (e.g. this ...
0
votes
0answers
75 views

Electron positron collision producing mesons

An electron of an energy 9 GeV and a positron of energy E collide to produce a $B^0$ and anti-$B^0$ meson, each with a mass of 5.3 GeV. What is the minimum positron energy required to produce the ...
1
vote
1answer
65 views

How do I handle elastic contacts in a simulation with friction [closed]

I'm trying to simulate a wheel as it hits the ground. Problem 1 Suppose a disc is dropped from a height. It has initial velocity of $-x,-y$ caused by throwing and gravity. It has no initial angular ...
1
vote
1answer
47 views

Help with my bouncy ball lab (I know the factors just not how to approach them) [closed]

In my physics lab we need to determine the factors that account for the energy "loss" during a high bounce ball bounce. I know that energy is "lost" (not really) to heat, air resistance, and sound. ...
1
vote
1answer
69 views

What is the conditions to excite an atom by collision?

I know that an atom can become excited in one of two ways: by absorbing some energy from a source of electromagnetic radiation or by colliding with some other particle—another atom, for example, but ...
2
votes
1answer
300 views

Proving the conservation of 4-momentum for a particle collision $A+B\to C+D$

Let me say that particle A hits particle B and two particles come out - C and D; In system S I can write: $$p_A^μ+p_B^μ=p_C^μ+p_D^μ;\tag{1}$$ here $p_N^μ$ is the 4-momentum. Using the Lorentz ...
1
vote
0answers
58 views

How can we solve 2D rigid body collision? [duplicate]

I know that usually collision with velocity collinear can be solved by simultaneous equations of both conservation of energy and linear momentum. But my question is when 2D velocity is encountered, we ...
2
votes
1answer
167 views

Is my proof of the thought experiment that Walter Lewin proposed in lecture 16 valid? [closed]

A tennis ball bounces off a wall elastically. The momentum of the wall changes, but the kinetic energy of the wall remains zero. How is that possible? Walter Lewin Lecture 16 - Ball bouncing on ...
1
vote
0answers
27 views

Relativity collision problem [closed]

Here is the problem: A body of mass m (I assumed this is rest mass, but not 100%), and momentum p(subscript m) collides with a stationary particle of mass M. Find the available energy in the CM ...
0
votes
2answers
71 views

Conservation of angular momentum in a collision

Suppose I have a stick hinged to a pivot and it is released from its horizontal position and just after it becomes completely vertical, it strikes a ball completely stationary as in the given figure ...
1
vote
6answers
129 views

How is momentum conserved when is is only dependent on mass and velocity, and so many other factors come into play?

I've been trying to get a good grip on the difference between conservation laws. Momentum is particularly tricky, I don't understand how quantities like $m\mathbf v$ can be conserved when other things ...
2
votes
3answers
95 views

Head-on collision between two neutrons

If two neutrons were set to collide head-on, being electrically neutral: Will they feel each other's presence due to electrostatic interaction between quarks of approaching neutrons? When they ...
0
votes
0answers
300 views

Speed of a magnet

What is the speed of two magnets during the congruent moment of their attraction? Theoretically, could a large enough magnet attract a significantly smaller magnet at near the speed of light? In ...
1
vote
1answer
50 views

How do I solve for $v_2$ where $mv_1^2 + MU_1^2 = mv_2^2 + M U_2^2$ and $MU_1 - Mv_1 = MU_2 - mv_2$ by eliminating $U_2$?

I was trying to solve the head on collision slingshot problem where the rocket moving with speed $v_1$ approaches a planet which is moving with speed $U_1$. I wanted the final speed of the rocket ...
5
votes
4answers
231 views

Why the round trip instead collision time?

From Newton's second law, the $\Delta t$ is defined as the collision time, but why in this case, it can be assumed to be the value of time between successive collisions on 1 wall? If I have an ...
1
vote
2answers
265 views

Collision of two satellites

In a theoretical situation in which two identical satellites travelling around the Earth in opposite directions collided head on so that there velocities relative to the earth both became 0, would ...
0
votes
0answers
24 views

Does final velocity after collision depends only on temperature change

An inelastic collision causes translational kinetic energy to be transferred into vibrational kinetic energy. Total kinetic energy is conserved. We measure the decrease in translational kinetic energy ...
0
votes
1answer
26 views

elastic collission

During an elastic collision some of the macroscopic kinetic energy is transferred to kinetic energy of the microscopic parts of the colliding bodies. The momentum is conserved, so the sum of the ...
1
vote
0answers
52 views

Plastic deformation energy dissipation due to inelastic collision

I have been attempting to determine an analytical expression for the coefficient of restitution (or any similar collision parameter) for an inelastic collision. So far, I've looked at Hertzian contact ...
0
votes
1answer
40 views

New direction vector after collision of spheres [closed]

I have a volume in 3-space in which random spheres are spawned in motion. They have the following attributes to them: position known (in three axes) a direction vector (in three axes) a scalar speed ...
2
votes
2answers
318 views

Why does a continuous water stream form ripples when colliding with a surface? [duplicate]

I was in the shower one day washing my hair, and noticed that the water falling off my hair formed perfect streams that ceased to break into droplets for quiet some distance (probably about 5-6 cm). ...
0
votes
0answers
50 views

Elastic Collision of Infinitely Large Body and an Infinitely Small Body

So I guess this is a somewhat conceptual question. There are two bodies, one with a mass $m$ that is so light it is massless and at rest so $v_{_i1} = 0$ And the other with mass $M$ that is almost ...
0
votes
1answer
30 views

Momentum equation in collision of a particle and a droplet

When a solid particle which moves with a constant velocity has a head-on collision with a water droplet, at the exact moment of collision, a sudden decrease happens in particle velocity, and then ...
3
votes
2answers
122 views

What happens when two bodies collide in a dynamics point of view?

I'm a high school student learning about energy and momentum. What confuses me is the things with elastic and inelastic collisions. I completely (in my opinion) understand those concepts in energy ...
3
votes
2answers
129 views

What makes objects fly out of bike basket?

When riding a bike on a bumpy road, objects (let's say, a baseball weighing 150 grams) sometimes fly upwards and out of the basket. However I cannot seem to be able to explain this physically. ...
0
votes
0answers
36 views

kinetic energy of flowing fluid

When a quantity of fluid (let's say equal to volumetric flow rate Litre/s) collides during a second with an object, do all the molecules of this quantity collides with it? I am asking this question ...
11
votes
1answer
1k views

Can a pool ball change direction mid-roll?

In this youtube video, a pool shark consistently gets the cue ball to drastically change direction mid-roll (i.e. while after he's hit it). Is this theoretically possible without using trick balls? If ...
0
votes
1answer
34 views

Rigid Balls aligned along a line in vacuum

Recently I've been trying to visualize a situation where i have these really rigid identical balls aligned along a line so close to each other in vacuum.Now if I were to apply an impulsive force to ...
1
vote
2answers
150 views

Elastic collision between two circles [duplicate]

I am trying to calculate the final velocities of two equal mass 2-dimensional circles after an elastic collision. I have tried to figure it out using formulas I know from high school physics, but ...
0
votes
0answers
8 views

Discrepancy of capture from 2p+1 state to 2p(+-1)

In the (nlm) characterization of hydrogenic orbitals. Consider the collisions H+ + H(2p+1) ---> H(2p-1) + H+ H+ + H(2p+1) ---> H(2p+1) + H+ where an electron capture has ocurred. Should the ...
0
votes
1answer
24 views

Coefficient of restitution belongs to kinetics and not to kinematics?Reason

The Coefficient of restitution is defined as $$e=\frac{v_2-v_1}{u_1-u_2}$$ $$v_2\to \text{final velocity body 2}$$ $$v_1\to \text{final vel of body 1}$$ $$u_1\to\text{initial vel of body 1}$$ ...
2
votes
2answers
169 views

Is the reaction force for a stone hitting a wall infinite?

Let us assume a rigid stone which moves in empty space with a constant speed of $v$. (Or in the air with no friction and drag or you can imagine a free fall with friction). This stone hits a rigid ...
0
votes
2answers
50 views

Is Buoyant force a reaction?

When we fall on water. The surface molecules are pushed down and as a consequence molecules below the surface molecules and molecules beneath them and so on are also pushed down. Some of them are ...
0
votes
2answers
56 views

Energy release on impact

I was watching this video from a video game showing a space ship travelling towards a planet at 22% the speed of light. The ship system pulls the ship out of this "quantum travel" just in time to ...
2
votes
1answer
548 views

Can solids behave like liquids?

Basically, the more I look at things the more it seems like there's entirely no difference between a liquid and gas, it all just depends on the relative density of what's around it. This being said, ...
0
votes
2answers
161 views

What happens if a motorcycle going at 50mph crashes head into a car going at 60mph? [closed]

I wonder if a motorcycle (going at 50mph) crashes into a car (going 60mph), what is the damage that motorcycle will experience? Here's a diagram that shows what I've in mind: ...
0
votes
2answers
112 views

Conservation of Mechanical Energy Before and After Impact of a Hammer

If a hammer does work by driving a nail into a wooden board, how does the mechanical energy from right before the hammer hits the nail compare to the mechanical energy after the nail has been driven ...
0
votes
1answer
39 views

Conservation of momentum in inelastic conservation

Why does momentum and velocity change along contact normal but not contact tangent In in elastic collision? Suppose a ball strike an inelastic surface. It's velocity component does not change along ...
1
vote
3answers
124 views

Researching an automobile accident.Wondering if someone can help me as I never studied physics [closed]

I am trying do some independent research on a recent auto collision where the information released doesn't seem plausible based on the pictures that I have seen of the accidents aftermath. A ...
1
vote
2answers
82 views

How does general relativity explain the impact force after radial inward fall toward Earth?

I understand that, in the context of the Schwarzschild spacetime (General Relativity), a radially inward falling observer follows a time-like geodesic with zero four-acceleration. There are no forces ...
0
votes
0answers
96 views

Glancing collision question

Can someone explain the energy loss in a glancing collision to me? And how this compares with head-on collisions. I know head-on collisions are when objects rebound on straight line paths that ...
1
vote
2answers
66 views

Resources for droplets investigation

I am interested in investigating droplets mechanics. I have read some documents and journal papers related to some aspects of (water) droplets e.g. surface tension, collision with flat surfaces or ...