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.
My initial thought was to use the conservation of energy law since there're no external forces acting on the system bullet + rod. The rod is in rest, the bullet is moving. Then after the collision, the bullet and the rod are rotating around the pivot together, so the kinetic energy of the bullet...
A simple model often used to explain solar system gravitational slingshots is to consider a mass moving to the right with initial velocity v1i and a much larger mass moving to the left with initial velocity v2i. After the collision, the first mass is moving to the left with velocity v1f and the...
Homework Statement: an object has a total mass of 75kg and is stationary, it then ejects as a smaller object to the left with a velocity of(+ve direction)7 ms-1(v2) with a mass of m2 , the original object then recoils backwards to the right (-ve direction) at a velocity of -2 ms-1 and a mass of...
My teacher wants me to know how to solve for missing values in a 1D collision when v2 does NOT equal 0.
Could someone do me a huge favour and make me a practice question to solve for a missing value when v2 does not equal 0? Or even point one out to me online?
And then let me try it out and...
initial total KE= (1/2)(0.6kg)(8m/s)^2 = 19.2J
(0.6kg)(8m/s) = (0.6kg+1.8kg)(vf)
vf= 2m/s
final KE= (1/2)(0.6kg+1.8kg)(2m/s)^2 = 4.8J
I tried to use linear speed=angular speed * radius : thus
2m/s= angular speed * (3.3m/2)
angular speed= 1.2 rad/s
Apparently that is wrong.
Homework Statement: Verify the claim of Section 7.2 that the electrons of a metal collide with the surface at a rate of about 10^30 per second per square centimeter. Do this by estimating the collision frequency of electrons in a 1.00-cm cube of copper metal with one face of the cube surface...
So after not being able to solve this problem I did some researching online. I was looking around and came across this video, where they give the following equations for solving for the final velocities of both balls:
v1f=((m1-m2)/(m1+m2))*v1i
v2f=(2m1/(m1+m2))*v1i
I plugged in my numbers and...
From what I understand, a black hole can exist that was formed entirely from antimatter. If this antimatter black hole were to collide or merge with a black hole that has the exact same mass, but was made of regular matter, what would happen?
Obviously the matter and antimatter would...
At the time of asteroid impact 65 million years ago wiping out the dinosaurs and 50 % of all life on Earth - presuming all but the smallest mammals or sea creatures suggests that humans most likely wouldn't be here today if not for that event because the tiny mammals which then existed would not...
If the initial kinetic energy is equal to the final kinetic energy where two objects that collide stick together, this collision is elastic or inelastic?
I have an example from my machinery handbook which shows the kinetic energy of a pile driver and shows it will drive a pile some distance at a force until the energy is expended.
The formula is (Average force of blow times distance)= Weight of object (driver) times distance it falls)
Just...
I recently heard in the news that the small asteroid Apophis will be so close to Earth it will be within the Earth's satellite orbits. This asteroid will likely not hit earth, even if it did it wouldn't have an extinction level impact. But there will come a day when we will have to face off with...
Hey everyone
I'm struggling on the last part of this assignment. I need to find the total work done by the block and the bullet, when the collision happens. The informations is:
mblock=0.3 kg
mbullet=0.01 kg
vg=700 m/s
Height=0.72m
The final speed after the collision is vf=22.6 m/s and the...
I need to develop some kind of simplified formula that will allow me to estimate pitch and volume of a sound of two colliding objects in a simulation. It doesn't have to be exact, mostly it is enough that it follows the intuition - large object produce lower sounds, large and fast object produce...
Okay, say we have two balls(equal mass and size), 1 and 2. #1 has kinetic energy and #2 is at a standstill, they collide. Ignore all friction, heat, sound losses etc..
Now I know that 1 exerts a force on 2, hence doing work, which in turn uses its kinetic energy up. Therefore, 2 speeds up...
How can I calculate the ACCELERATION of a stationary steel ball after being hit by a moving steel ball.
I know how to get the final velocity but how long does it take to accelerate to that velocity from zero?
Does it depend on the elasticity of the materials?
I guess we need to know long did...
Can someone explain me (even in poor worda) the relationship between collision and relaxation? I mean, a structure is relaxed when the particles (or stars) inside have frequent collisions? Or not?An elliptical galaxy is a relaxed structure. Can i deacribe the internal stars with a...
I've come up with the following causes:
- air resistance
- parallax
- during the collision, some of the kinetic energy gets converted into thermal energy.
- invisible deformations
But I'm not sure which would be the biggest effect on the total momentum change.
Are there any other reasons that...
My approach:
Let us take two orthogonal axes: x, parallel to the racket's plane and y, perpendicular to it. For the ball to not spin, the components of initial velocities of the racket and the ball along x-axis must be same. Also, as the line of collision is along the normal to the racket's...
I calculated that the velocity of the head prior to the collision is sqrt(2gh), as all of the gravitational potential energy is converted to kinetic energy.
And I believe the velocity at point A after the collision is given by the formula vf=e•sqrt(2gh), with e representing the coefficient of...
This seems like a fairly simple problem but I got the same answer for both so I'm unsure if I am doing it right.
I found the accelerations as such
a1 = (fk)/(ma) = (98/20) = 4.9 m/s2
a2 = (fk)/(ma) = (73.5/15) = 4.9 m/s2
Am I doing something wrong or is this problem just that simple?
I was wondering why in the video the moment of inertia for the clay ball (upon collision) was simply 1ml^2. That is the constant for a hollow cylinder. The problem specifies that the object is a ball, so the cylinder classification makes no sense, and also I'm pretty sure clay is rather dense...
a) Let m be the vehicle's mass, M the truck's mass, vt the truck's speed, vc the car's speed, vf the final speed, θ the angle both vehicles make with the horizontal axis (west-east direction) after the collision.
Conservation of linear momentum:
In the x direction: M vt = (m + M) vf cos(θ)
In...
Considering the quantum mechanical model for an atom, what exactly happens when two atoms (say, two Ca2+ ions in a Brownian motion) collide with each other? As I know, this collision is not like a regular elastic or inelastic collision between two macroscopic objects. Is it mainly due to the...
They collide when their positions are the same, so I plugged the information for the boat into equation 1 to get an expression for d which is (2i, +j)t^2
Then I used equation 4 to get an expression for d for the branch, which is (-4i, +j)t
I would need to take into account the different...
Good Morning
May I ask about spatial collisions of bodies?
In undergraduate dynamics, we study that when two particles college, we have two final unknowns: the final velocity of each particle.
We first use the conservation of linear momentum.
However, we supplement the analysis with the...
The speed of the sphere after the impact will be the same since the collision is elastic and the kinetic energy remains the same. So the change of momentum will be given by the cosine law right? What bothers me is the second question about the force that acts on the sphere (which can be given by...
The problem I have here is that I can't see how the restitution coefficients (e) will change the trajectory of the ball since the speed of the ball B will be on the same direction as the normal component.
And without information one the ball A, I can't see how to resolve that.
I will really...
Homework Statement
[/B]
Ball with a mass of 0.1 kg travels at a speed of 10 m /s to the boy.
Boy kicks the ball with foot so that it bounces back at an angle of 30 degrees with respect to the horizontal floor. The ball falls back to the ground 20 meters from the boy.
With what average force...
Homework Statement
Homework Equations
m2 = E2 - p2 ([/B]The Attempt at a Solution
I got stuck by not knowing how to handle the frames and I thought you can view the Z boson (CoM) frame, but then you simply get that mz = 2me
Homework Statement
A 39,000 lb truck A and a 3968 lb sports car B collide at an intersection. At the moment of the collision, the truck and the sports car are traveling with speeds vA = 70 mph and vB = 30 mph. Assume that the entire intersection forms a horizontal surface. Letting the line of...
Homework Statement
A particle with mass M and speed v along the positive x-axis hits a stationary mass m. Two particles, each with mass µ, emerge from the collision, at angles with respect to the x-axis.
(a) Write the equation for conservation of the 4-momenta, for arbitrary angles θ_1, θ_2 of...
Hello. I recently began this problem, but the site I'm working this problem on isn't showing me whether the answer is correct or not. Can someone please check my work and just verify that it's correct or state if it isn't and why?
1. Homework Statement
A cosmic-ray photon (with mass m...
Imagine a carom shot in a perfect world.
A ball travels diagonally from the lower left-hand corner towards the right cushion and bounces off to head towards the upper left-hand corner.
The ball has X and Y momentum. On the collision, the cushion absorbs and then return all the -X momentum to...
How small should ##\Delta T## be in a collision to be considered elastic? In elastic collisions ##\Delta T =0##, but as far as I know, just atomic collisions are considered perfectly elastic. Then, which criterias are used to considere a collision between two objects elastic?
Homework Statement
A locomotive has broken through the wall of a train station. During the collision, what can be said about the force exerted by the locomotive on the wall?
a)The force exerted by the locomotive on the wall was less than the force exerted by the wall on the locomotive.
b) The...
My concern is an electron tube.
From what I understood so far, gas molecules will have an average velocity derived from the Maxwell distribution, and that velocity will influence in the electron collision frequency.
I can't see clearly though how the electron velocity itself in the presence...
If, as suspected, the Andromeda galaxy "colides" with our own sometime in the far future, would the gravitational forces from passing stars have effect on our solar system?
In accelerated models the interaction looks quite violent, but how would it be in our "uncharted backwaters of the...
Hi Folks,
I've read that by the time mankind is ready for intergalactic travel, our nearest galactic neighbour will be too far to even travel to. But I've also read that Andromeda is on a collision course with the Milky Way. Which is correct? And if the universe is expanding and everything is...
Homework Statement
In perfectly elastic collision between two atoms, it is always true to say that
a. the initial speed of one atom will be the same as the final speed of the other atom
b. the relative speed of approach between two atoms equals their relative speed of separation
c. the total...
Let's say you have a low force hobby robotic arm that's supposed to perform a certain movement, but it should stop if there is an object in the way. What sort of sensors/solutions exist for this?
I've considered force sensors but I'm not sure if that's the best idea since I'd have to place many...
Homework Statement
A passenger train is traveling at 29ms^-1 and a freight train is traveling 360m ahead of it at 6ms^-1 in the same direction on the same track. The driver of the passenger train has a reaction time of 0.4s before he starts decelerating. What is the minimum deceleration to...
I have been searching for an answer to this for a really long time and I have not found any definitive answers as of yet. What I am trying to do is determine if and when two bodies collided between the times t0 and t1. Calculating this is much more straight forward if each body is only either...
Homework Statement
Two hockey pucks collide in a 90 degree angle and stick to each other. What's the speed of the hockey pucks after the collision and in what angle are the pucks moving in.
Homework Equations
m1=0.71kg
m2=0.52kg
v1=1.6m/s
v2=3.8m/s
The Attempt at a Solution
m1v1+m2v2=v(m1+m2)...
Homework Statement
When a train traveling at 161 km/h rounds a bend, the engineer sees that a locomotive has entered onto the track from the side and is a distance D=676m ahead. The locomotive is moving at 29 km/h. The engineer of the high speed train immediately applies the brakes.
What must...