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.
Homework Statement
Asteroid A is traveling at 40.0m/s and collides with asteroid B which is at rest. Both asteroids have the same mass, but asteroid A deflects off of its path by 30.0° above the horizontal, and asteroid B begins to travel 45.0° below the horizontal. What is the speed of...
Homework Statement
Homework Equations
http://en.wikipedia.org/wiki/Simple_harmonic_motion
The Attempt at a Solution
So I labeled the image at the points of interest where I would need to calculate certain values.
for part a)
so from A --> B
All I'm trying to figure out...
Homework Statement
A 110 kg football player runs at 2.75 m/s directly into a 125 kg player running 2.60 m/s towards him. What is the kinetic energy of the two players if this is a completely inelastic collision.
Homework Equations
P = m*v
Ptotal = Pi - Pf
K = 0.5*m*v^2
The...
Here is the problem I am trying
Two blocks A and B of same mass M are connected with
each other with an ideal string of length 2l passing over an
ideal pulley. The block A is connected to a light pan C
with an ideal string as shown in figure. A particle of mass
\frac{M}{2} is dropped on...
I solved the question , but i need to check it with you guys ... I believe there is something wrong with part b .
Homework Statement
The 15000kg train A is running at 1.5 m/s on the horizontal tack (to the right) when it encounters a 12000kg train B running at 0.75m/s toward it (to the...
I've got a question that asks what the maximum scattering angle in \nu_\mu e \rightarrow \nu_\mu e is. The electron is stationary in the lab frame and after the collision has E >> m_e.
The answer given is
\sqrt{\frac{2 m_e}{E_e}},
independent of the neutrino's energy. How can I get...
Homework Statement
A bullet with mass mA and velocity vA makes a completely inelastic collision with a still pendulum of mass B. After the collision, the pendulum swings to a height of y from its equilibrium with the bullet in it. In terms of y, mB and mA, what is the initial velocity?
My...
1. Two carts, each of mass M, travel towards each other on a frictionless air track, one with velocity V, and the other with -3V. They collide and stick together. How much kinetic energy is lost in the collision?
2. P = mv, KE=1/2mv2
3. Initial KE of the system is the sum of the kinetic...
I'm trying to find out the force on a collision that happened to me recently, nothing serious but the lady went away in the ambulance for what I believe wasn't that much force exerted on her at all.
Both vehicles were at a stationary position about 2.5 meters away from each other. The second...
Homework Statement
Homework Equations
Zero-momentum frame is defined as the frame in which total momentum is zero.
The Attempt at a Solution
(a) In terms of the zero momentum variables, (e1 and e1 are to distinguish the two resultant particles)
\vec{p'}_{HE} +...
A 1689 kg car collides head on with a 2000 kg truck. The collision is elastic. If the velocity of the truck is 17km/h in the same directions as the car's initial velocity, what is the initial speed of the car in km/h?
I'm getting an answer but doesn't seem to make sense.
So I'm...
Homework Statement
A small ball of mass, ##m_1## is aligned above a larger ball of mass ##m_2=0.63kg##, with a slight seperation. The two are dropped simultaneously from a height ##h=1.8m##(Assume the radius of each ball is negligible relative to h.) (a) If the larger ball rebounds elastically...
Two blocks m1 and m2 are connected by an ideal spring of force constant k. The blocks are placed on smooth horizontal surface. A horizontal force F acts on the block m1. Initially spring is relaxed, both the blocks are at rest.
What is maximum elongation of spring?
i think it would be when...
Homework Statement
Question: First image
My working: Second image
I used Va+Vb for the speed of separation. I got the answer for (a), but couldn't get the answer for (b).
I know the proper expression is "Vb-Va" with Vb being negative.
But if I use Vb-Va, (a) would be wrong.
How come...
Homework Statement
A geostationary satellite of mass m, speed v orbits earth.
(a) Find expressions for
(i) Radius of the orbit, r0.
(ii) Satellite's Speed
(b) A meteorite with mass m and speed v approaches in the direction towards the centre of the Earth and collides with the satellite...
Homework Statement
There are 2 pucks with different masses. Puck 2 is initially at rest, and Puck 1 is moving horizontally in the positive x direction. The collision has sent the pucks off at angles θ1 and θ2 measured relative to the x-axis, along which Puck 1 initially traveled. Assume...
Homework Statement
A mass, m1 = 4.5 kg is released form rest 2.5 m above the ground on a inclined plane (35 degrees). m1 slides down incline and makes a smooth transition to flat plane then strikes m2 = 8.2 kg, which is at rest, calculate the speed of both masses after elastic collision and...
Homework Statement
A photon of Energy E_0 collides with a free particle of mass m_0 at rest. If the scattered photon flies off at angle θ, what is the scattering angle of the particle, β?
Homework Equations
The relevant equations are conservation of momentum in x and y direction and...
What would happen if two large planetary masses (such as our earth) collided by their poles (ie, north hits north)? Would the repellent magnetic force be negligible compared to the masses and gravity, or would the collision be altered or averted?
Also, while I am thinking about it, what size...
Homework Statement
There's an elastic collision between a photon of energy E and an atom in an excited state. After the collision, the energy of the photon is still E but its direction changed of angle of 180° and the atom is now going back with velocity Bc. If the atom is in his ground state...
Homework Statement
If the truck was not stationary but was moving horizontally towards the ball at 25 ms-1, what would be the speed of the ball, relative to the ground, after the collision (in ms-1)?
Mass of ball = 0.2 kg
Mass of truck = 20 tonnes
Initial velocity of ball = 20 ms-1 (to the...
Homework Statement
Hello everybody ,
a/There's an elastic collision between a photon of energy E and an electron at rest. After the collision, the energy of the photon is E/2 and propagates in a direction making an angle theta=60° with the initial direction. Find E. What kind of photon is this...
Homework Statement
A 10.0 g marble slides to the left with a velocity of magnitude 0.400 m/s on the frictionless, horizontal surface of an icy New York sidewalk and has a head-on, elastic collision with a larger 30.0 g marble sliding to the right with a velocity of magnitude 0.200 m/s.
Find...
Hello,
I am trying to simulate collisions between polygons with opengl.
The weight, velocity (as a 2d vector), the angular velocity and the collisionpoint of the colliding polygons are provided.
How can I calculate how the angular velocity and the velocity are changed?
I do know how i...
Help needed -- collision of two snowmobiles
Homework Statement
A police officer arrives at the scene of a collision of the two snowmobiles to find both drivers unconscious. When two vehicles collided, their skis became entangled and the two snowmobiles remained locked together as they...
Homework Statement
A billiard ball moving at 5.40 m/s strikes a stationary ball of the same mass. After the collision, the first ball moves at 4.48 m/s at an angle of 34.0° with respect to the original line of motion. Assuming an elastic collision (and ignoring friction and rotational...
Two objects of mass M (= 1 kg) each travel with identical speed (|v1| = |v2| = 3 m/s) making an angle of θ relative to the x-axis. After they collide with each other, they travel as one object of mass 2M and with a velocity v3 (|v3| = 2 m/s) in the horizontal direction.
What is the value...
Homework Statement
"A body of mass m, moving with velocity v, collides with a body of mass 2m at rest, in a head-on collision. The coefficient of restitution is 1/3. If the 2m body has a specific heat c, and if it is assumed that the two bodies share the heat generated in the collision equally...
Homework Statement
The figure (Figure 1) is an incomplete momentum bar chart for a collision that lasts 15ms .
Figure 1: http://session.masteringphysics.com/problemAsset/1384208/4/knight_Figure_09_06.jpg
What is the magnitude of the average collision force exerted on the object?
Express...
Homework Statement
A ball of clay of mass m travels with velocity v in a path tangent to a disk of radius R and mass M. The clay collides with the disk tangentially to its outer rim ( a totally inelastic collision) and the clay and disk begins to spin about the axis.
a) What is the final...
Homework Statement
I throw a ball horizontally
During the first collsion between the ball and the floor
Select one:
a. Both horizontal and vertical momentum of the ball are conserved
b. The horizontal momentum of the ball decreases and the vertical momentum decreases
c. The horizontal...
Homework Statement
A 2kg block is resting on a frictionless table. It is hit, head on, by a 1kg block heading at 4 m/s. The larger block is sitting 3m from the edge of a 5m long table. The collision happens with the smaller block's distance being 2m from the table and the larger blocks d =...
English is not my native language.
My question is about what happens when we throw a ball on the floor. I understand why the ball bounces off it. But I have a question, I wonder why almost all the kinetic energy get back to the ball, rather than lost in the land, that is, why this energy is...
I wanted to check some concepts in collisions because I'm a little bit confused.
In a real-world collision (Where everything applies, friction and so on) conservation of momentum doesn't really apply because there is friction, which is an external force.
1)That is the only reason momentum...
A mass m1 = 6.20 kg is moving North with a velocity of v1 = 13.5 m/s when it collides perpendicularly with another mass m2 = 4.40 kg moving East with a velocity of v2 = 8.80 m/s. Mass m1 runs into mass m2 in an inelastic collision and both masses stick together and move off after the collision...
A ball, which has a mass of m1 = 2.50 kg., is moving with a velocity of 8.00 m/s at an angle of 25.0˚ South of West. It collides with a second ball, which has a mass of m1 = 1.20 kg., which is moving with a velocity of 4.75 m/s at an angle of 61.0˚ North of West. They stick together and move as...
I have problems with a(ii). (please view the first image.)
Now I have found that w = (13-8e)u/7 and v = (20e+13)u/7
What I did is like this:
(Using NEL)
v = 4ue
Where the LHS is actually v-0 because I assume Q = 0.
(20e+13)u/7 = 4ue
e = 33/28 >1 ∴ e cannot exist.
1. Is...
car-wall collision problem (urgent)
Homework Statement
What net force is acted upon the car by the wall during the collision. Explain your answer along with what assumptions you made.
Homework Equations
The Attempt at a Solution...
Homework Statement
A cue ball with speed U hits a stationary red ball of equal mass. The collision is elastic (ie no energy is converted into other forms). After the collision the cue ball is moving at an angle θ to its original path. Find the final speed of the cue ball.
Homework...
Homework Statement
A billiard ball of mass 0.162 kg has a speed of 1.86 m/s and collides with the side of the billiard table at an angle of 51.8°. For this collision, the coefficient of restitution is 0.841. What is the angle relative to the side (in degrees) at which the ball moves away from...
The Drude theory assumes the probability that an electron makes a collsion in a second with probabilty 1/ζ where ζ is the relaxation time. Since ζ can be any positive number, the probability can get greater than 1.
What does this mean?
Homework Statement
Consider a 2-D elastic collision between two masses. The first mass is moving at initial speed v0 towards the second mass. The second mass is initially at rest. Mass m1 = 0.1 kg and mass m2 = 0.2 kg. The first mass recoils at 30° above the horizontal at speed v1, and the...
Homework Statement
Solve the Boltzmann equation for a homogeneous plasma with not external forces present when the collision term is
\frac{\partial f(v,t)}{\partial t} = -\nu (f(v,t) - f_0(v)),
where \nu and f_0 are constants.
Homework Equations
Boltzmann equation
\frac{\partial...
Homework Statement
Consider a blackbody contain atoms that typically produce photons with energy of about 7eV. Estimate the number of photon-electron collision each photon undergoes before it escape the object. Assume the blackbody has a temperature of 1000K.
Homework Equations
λ2 - λ1...
Homework Statement
A 3.000 u (1 u = 931.5 MeV/c2) object moving to the right through a laboratory at 0.8c collides with a 4.000 u object moving to the left through the laboratory at 0.6c. Afterward there are two objects, one of which is a 6.000 u object at rest.
A) Determine the mass and...
Hi, I just have a quick question I hope I can explain well.
Suppose you have a metal rod that you apply a force to for a brief moment at the center of mass. It won't rotate and it will move forward at velocity V. Now you reset the scene and move the the force so it's applied off center off the...
Homework Statement
A 5.0 kg block with a speed of 8.0 m/s travels 2.0 m along a horizontal surface where it makes a head-on, perfectly
elastic collision with a 15.0 kg block which is at rest. The coecient of kinetic friction between both blocks and
the surface is 0.35. How far does the 15.0...
Homework Statement
A particle of mass m traveling at a velocity u makes a perfect elastic collision with a stationary particle. After the collision both particles are observed to be traveling in directions making angles of 30 degrees to the original path of the first particle.
a) Use the...
Homework Statement
I'm only interested in the second part where V << v
Homework Equations
Energy
The Attempt at a Solution
First I boosted to the frame of the moving wall to find the change in velocity of the ball after a collision with it. In the frame of the moving wall...