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.
There is 4 parts to this one question.
A 2.0 Kg block is traveling to the right with a velocity of 3.0 m/s. The block collides with a stationary 1.0 kg block and the blocks bounce apart (elastic collision).
1. Homework Statement
(a). if the velocity of the 1 kg block is +4 m/s after the...
Homework Statement
Homework EquationsThe Attempt at a Solution
How do I calculate part d?
I know that (m2-m1)v0 = m2v2+m1v1
where v0 = root (2gh), v1 and v2 are the new velocity of the masses
(m2+m1)v02 = m2v22 + m1v12
I also know that v2-v1=2v0
but how do I separate the KE of mass 2?
Homework Statement
1. Two skateboarders start from rest on opposite sides of a ramp like the one in the image, roll down and collide elastically on the level part of the ramp. The masses of the skateboarders are m1 = 48 kg and m2 = 55 kg and they both start from the height h = 4.70m. Ignoring...
Homework Statement
A particle A of mass m and initial velocity v collides with a particle B of mass m 2 which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths λA to λB after the collision is
Homework Equations
u initial velocity
v final velocity
The...
Homework Statement
A 0.170-kg baseball pitched horizontally at 36.0 m/s strikes a bat and is popped straight up to a height of 36.0 m. If the contact time between bat and ball is 2.0 ms, calculate the magnitude of the average force between the ball and bat during contact.
##m_b=0.17kg##...
What object in the universe (neutron star, supernova, black holes, pulsars) can cause the most powerful collision and what energy is the plasma produced? I'd like to know how many GeV of plasma it can make as the minimum.
Homework Statement
Find the 2 unknown variables.[/B]Homework Equations
Am I doing this right? Can someone help me find the solution?[/B]
The Attempt at a Solution
To compute for the velocity of the target/arrow combination immediately after the collision:
M_bV_{bi}=M_bV_{bf}+M_wV_{wf}...
Homework Statement
Ball A is dropped from rest from a building of height H exactly as ball B is thrown up vertically from the ground. When they collide A has twice the speed of B. If the collision occurs at height h, what is h/H?
Homework Equations
(I would type them out put I can't format...
Homework Statement
A mass 1.3 kg is initially at rest at the top of a 1.8 meter high ramp. It slides down the frictionless ramp and collides elastically with an unknown mass which is initially at rest. After colliding with the unknown mass, the 1.3 kg mass recoils and achieves a maximum height...
Homework Statement
Two balls with mass m and 4m collide at the location x=y=0 and stick. Their initial velocities just before the collision can be represented as v1=(i+j) v and v2=(j-i)v' respectively. Their final velocity vf makes an angle θ with the +x axis. Find v and v' in terms of vf and...
Homework Statement
The questions showed in the pictures ask me whether the collisions in the drawings could be elastic or inelastic, I am not given any mass, the angles are a little vague but I think B and C are supposed to be π/2 and π respectively. For velocity, I am just given the direction...
Morning!
My question is this: If we consider a situation of mechanical collision, in the real world we shall observe certain loss of energy into heat or sound. Can we find mathematical equations to measure the amount of sound or heat produced using only mechanical variables, such as mass...
Homework Statement
Car bumpers are able to reduce the force of an impact by allowing the force to the spread over a greater duration of time. I am wondering how this affects the impulse between collisions because while increasing the time it is decreasing the force, both of which are...
fHomework Statement
Question b:
Homework Equations
E2=c2p2+m2c4
The Attempt at a Solution
We have c2pinitial2=E02-m2c4, and Ef2=c2p2+m2c4 for each outgoing proton. Combining those equations we get c2p2=Ef2-E02+c2pinitial2. I don't know where to go from here.
Homework Statement
Both object A and B have mass M and are moving.
An object with mass of m and moving with velocity u collide with the object B elastically. (m < M)
Find the following after m collide with B
1) Velocity of m after bouncing back
2) Velocity of B
Then m collide with A and bounce...
I was thinking about Newton's Cradle the other day, and I wondered how those collisions actually look like in detail. Which then got me thinking that my understanding of even a basic elastic collision of two macroscopic objects is weak to say the least.
Simplified, the two objects could be two...
Two spheres of different masses are dropped to ground.They are in contact as one above the other and are of masses, let’s say m and 2m.They are dropped with velocity v - My question is if we can conserve momentum and if we can why?And how to find the final velocity of upper ball after collision...
The collision of a billiard ball against a wall is considered elastic. Intuitively i can accept it. But analytically i don't understand it.
Why does the wall not take any relevant amount of energy from the ball? Is it connected to the change in temperature of the wall ?
What scenarios can we...
Hi all!
I was having a conversation with a (rather young) friend about the following imaginary situation- suppose you are in a helicopter, at rest relative to the ground. So you are basically seeing a 'top' view. Say you have a a wall fixed to the ground, and it is kept in the middle of a moving...
The rod is attached and can frictionlessly slide on the purple track. The questioner specified that the collision is elastic. The first obvious error in this problem is that the direction and magnitude of the final velocity of the ball is impossible. If the ball carries off all the energy it...
Homework Statement
Homework Equations
Total Ke initial - Total Ke final = lost KE
P= m1v1 + m2v2
The Attempt at a Solution
Initial P : sqrt((0.08*50)^2 + (0.06+50)^2)
Final P : (m1+m2)vf = 140vf
Initial P = Final P and solve for vf , vf = 0.0357
KE initially : .5(0.080)(50^2) +...
Homework Statement
Homework Equations
change in momentum = m1v1 = m1v1+m2v2
center of mass = m1x + m2x / (total mass)
The Attempt at a Solution
m1v1= m2v2 + m3v3
m1 = 2
v1 = 4
m2 = m1 divided by 2
m3 = m3 divided by 2[/B]
2*4 = 1*12 + 1v3
v3 = -4
v3= -4? in the x directioncenter of mass...
Homework Statement
A 1000 kg car approaches an intersection traveling north at 20.0 m/s . A 1200 kg approaches this same intersection traveling east at 22.0 m/s. The two car collides and lock together. Ignoring any external forces , what is the velocity of the car immediately after the...
Hi, as you can see at the end of the picture/attached file collision integral is approximated to a discrete sum. Could you express how this approximation is derived?
Probably a very simple question:
Does the coefficient of restitution depend on the collision being performed?
Consider two masses ##m_1## and ##m_2##. They are placed on a frictionless horizontal table and ##m_1## is given an initial velocity, collides 1-dimensionally with ##m_2##, and the...
Homework Statement
Two particles having mass m separated by a distance d is uniform magnetic field as shown in the figure . If v=qBd/m, at what instant does collision occur. The coulomb force between the particles is switched off.
Homework Equations
T=2πm/qB
The Attempt at a Solution
For the...
Homework Statement
These are two conceptual questions we were given recently. It's strange how mathematically I regularly do much harder problems but these caught me out a bit
Q1.
If a one snooker ball hits another ball moving at constant speed, why does the second ball move? Surely due to...
Homework Statement
[/B]
A mass ##m## travels in a straight line with velocity ##v_0## perpendicular to a uniform stick of mass ##m## and length ##l##, which is initially at rest.. The distance from the center of mass of the stick to the path of the traveling mass is ##h##. Now the traveling...
Homework Statement
Prove that in the elastic collision of two objects of identical mass, with one being a target initially at rest, the angle between their final velocity vectors is always 90 degrees.
Homework Equations
m1v1+m2v2 = m1v1'+m2v2'
1/2m1v1^2 +1/2m2v2^2 = 1/2m1v1'^2 + 1/2m2v2'^2...
Homework Statement
Homework Equations
Conservation of linear momentum
Conservation of angular momentum
##\frac{-v_{relative after collision}} {v_{relative before collision}}=e## where e is coefficient of restitution
The Attempt at a Solution
Components of velocity given as...
Homework Statement
In my reference frame, I see two carts collide. Both cart A and Cart B have a mass of 2 kg. Cart A has initial velocity v= 3 m/s i-hat + 2 m/s j-hat, cart B has initial velocity v= 3 m/s I-hat + 4 m/s j-hat. 12 J are released in the collision.
In previous parts of this...
Homework Statement
Suppose a heavy particle (mass m1) has an elastic head-on collision with a very light particle of mass m2 initially at rest. Show that if m1>>m2, the velocity of the projectile (m1) is practically unchanged, whereas the target particle (m2) acquires a velocity v2' = 2v1...
Homework Statement
I am currently solving a problem and I am not sure if it is correct.
There are two particles A and B. A has a constant velocity with |\vec{v}| = 3 and starts from y = 30
B has constant acceleration with |\vec{a}| = 0,4
The goal is to find the angle between the...
Consider the following extreme cases for a completely inelastic collision. In each case, determine the approximate ratio KEf/KEi.
a) A moving train collides with a stationary car.
b) A moving car collides with a stationary train.
I do not understand this question, I'm not given masses or...
Homework Statement
A billiard ball moves at a speed of 4.00m/s and collides elastically with an identical stationary ball. As a result, the stationary ball flies away at a speed of 1.69m/s, as shown in Figure A2.12. Determine:
the final speed and direction of the incoming ball after the...
Homework Statement
'A small smooth sphere moves on a horizontal table and strikes an identical sphere lying at rest on the table at a distance d from a vertical wall, the impact being along the line of centres and perpendicular to the wall. Find the distance from the wall of the next impact...
Homework Statement
A pendulum consists of a mass M hanging at the bottom end of a massless rod of length l, which has a frictionless pivot at its top end. A mass m, moving as shown in the figure with velocity v impacts M and becomes embedded.
What is the smallest value of v sufficient to...
Homework Statement
Three freight cars of equal mass are coupled together. The freight cars are traveling at 6.7m/s down a straight track when they collide with two more stationary identical cars. If all five cars are coupled together after the collision, then what is their speed if they are on...
Hello, I've been searching for a collision simulator for planets that uses SPH. I haven't found any though. US2 doesn't use SPH collisions. But does anyone know any that are publically available? Example video below:
And a channel with a few: https://www.youtube.com/user/joetaicoon/videos
Could someone please have a look at my solution and tell me if it makes sense. Although I am able to get the initial velocity that the question asked for, however the fact that I did not incorporate the y-component which is 1.2sin30 degrees into the solution makes me doubtful. If I do need to...
Homework Statement
A car initially at rest accelerates North for 10seconds. At 11seconds a second car heading west at (Time given in Km/h) collides with the first car at a cross intersection. The cars stick together and slide off across the intersection at (Vf given in KM/h). How much energy...
Homework Statement .
True or False:[/B]
For a completely elastic collision of two isolated masses the energy lost is
½μνr2
Where μ is the reduced mass of the system and νr is the magnitude of relative velocity between the two particles.
Homework EquationsThe Attempt at a Solution
Elastic...
1. 2. The equations are the equations of conservation of momentum:
m1v = m1v1cosθ1 + m2v2cosθ2
0 = m1v1sinθ1 + m2v2sinθ2
3. I tried to solve it using the above equations and also tried using kinetic energy conservation since it's an elastic collision. But I can't work out the...
1. Homework Equations
[/B]
P = mv The Attempt at a Solution
[/B]
VCos(30) + 0 = nCos(60) + 2Cos(20)
VSin(30) + 0 = nSin(60) + 2Sin(20)
where I let n = any speed,
I'm not sure if my attempt at the solution is correct.
Homework Statement
Before the discovery of the neutron, it was proposed that the penetrating radiation produced when beryllium was bombarded with alpha particles consisted of high-energy &gamma rays (up to 50 MeV) produced in reactions such as α + 9Be --> 13C + γ
a.) Calculate the Q value for...
Homework Statement
Suppose I have a system which contains two bodies m1 and m2 with initial velocities v1 and v2 , respecitvely.
they hurl toward each other and make an inelastic collision. such that they are now one body of mass
m1 + m2
I know that the difference in momentum is...
In what condition does a photon hit a proton? What happens to the energy of the photon in that case? Does proton emit another photon and goes down to the initial energy state?
How frequently is collision of stars in galaxies? If there are 100 bi galaxies and 100 bi stars each, then how many collisions should we expect in within, say, 1 year?