# What is Inelastic: Definition and 494 Discussions

In economics, elasticity refers to the measurement of a percentage change of one economic variable in response to a change in another.

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1. ### Fast and Furious Scene Analysis

The collision seems to be an inelastic collision meaning momentum is conserved however, energy is not due to likely thermal energy from the collision. Using conservation of momentum, we can maybe somehow find the initial momentum of each vehicle and set it equal to the final momentums? However...
2. ### Kinetic energy transfer from a rotating body in an inelastic collision

The cylinder in question would have a moment of inertia of ~1.67kg*m² and rotational KE of 2.058J. At the point of impact also, assuming the body hits the sphere at a 90deg angle after traversing 90deg of displacement, it should(?) exert a force of 1.31N - enough to give an acceleration of...
3. ### Momentum in a perfectly inelastic collision

I calculated:arctan(fy/13.0)=55=>fy=18.566 m/s Then I calculated, using the momentum equation: m1viy+m2v2iy=(m1+m2)vfy=> mv2i=2*m*18.566=>v2=37.132 m/s I thought that because the cars were stuck together, the kinetic energy from the northbound car would be lost. So, the speed would have...
4. ### Inelastic collisions with constant momentum

Kinetic energy before collision =1/2 mv² + 1/2 mv² = mv² (since energy is a scalar quantity, the direction does not matter). Kindly tell why am I not getting the required answer i.e: 1/2 mv². Am I doing the calculation wrong?
5. ### Inelastic collision followed by circular motion

Found the speed at which the masses will travel after their collision: 2.25m/s Not sure what to do next...
6. ### Perpendicular inelastic collision problem

I still don't get it where did "v" go. I'm trying to solve the problem that is on the second image. Second image.
7. ### Perfectly inelastic collision of two moving and rotating disks

two moving and rotating, uniformly weighted disks perfectly inelastic collide. The disks are rotating in opposite directions (see the diagram) At the moment of their collision, the angles between their velocity and the line connecting their centers are 45 degrees. The velocities are therefore in...
8. ### I Solving Relativistic Inelastic Collisions: 150 GeV Energy

Hi! Hope I'm posting this in the right place! I'm practicing for exams and came over this question: A proton with mass ##m_p## is accelerated to a relativistic velocity, with kinetic energy ##K##. It collides completely inelastic with another proton, which has the same kinetic energy, ##K##...
9. ### Engineering How much force will be experienced by the sidewall?

I have a V-shape depression (2-dimensional) with inelastic but deformable material filled. If the material is pressed atop, how much force will be experienced by the sides?
10. ### Inelastic collisions -- how is momentum conserved but not energy?

m1v1+m2v2=m1vs'+m2v2' , if car hits small fluffy object m2, initially v2=0, and v1'=v2' ... so m1v1=[m1+m2](v2') but why not energy? Why is there a KElost? .5m1v1^2+.5m2v2^2=.5m1v1'^2+.5m2v'2^2 +KElost , and again v2=0, v1'=v2' .5m1v1^2=.5[m1+m2]v2'^2+KElost using consv of momentum...
11. ### Calculate speed from elastic and inelastic collisions? (momentum)

So to cut to the chase, I missed my class' lesson on momentum - have tried to catch up, quite successfully but am baffled about this question. I know the conservation of momentum etc. but after trying for ages it's just not happening this question so any help would be much appreciated, Oscar.

13. ### Should I use arccosine instead?

Xcomp: [-(1500kg)(100km/h)(sin(30))+(3500kg)(70km/h)(cos(90))]/5000kg = -15km/h ycomp: [(1500kg)(100km/h)(cos(30))+(350(70km/h)(sin(90))]/5000kg = 74.98km/h
14. ### Application of momentum conservation in inelastic collisions

So, what I did was suppose the mass of ramp is $M_r$ and let velocity at B of block be v, then, after inellastic collsion both bodies v' velocity at B , $$M\vec{v}= M_r \vec{v'}+ M \vec{v'}$$ or, $$\frac{M}{M +M_r} \vec{v}= \vec{v'}$$ Now, Suppose I take the limit as mass of ramp goes to...
15. ### The inelastic collision between a disk and a rotating platform

A disk is dropped on a platform rotating at a constant angular speed ##\omega_i## as shown below. The question asks whether the final kinetic energy of the platform is conserved. I understand the angular momentum is always conserved provided that the net torque is 0, so I wrote the following...
16. ### I Relationship between Pileup and inelastic collision events

I've read some stuff on pileup.In one paper, it says the number of inelastic event approximately equals pileup event in detector.I don't quitely understand it.Can someone explain?Thanks
17. ### How momentum is conserved in an inelastic collision

In inelastic collision their is loss of energy and according to my current knowledge energy can be transferred by either work out heat...Now The problem is that we use law of conservation of momentum in problems related with inelastic and if energy is transferred from our system (two masses)...
18. ### Transition from Elastic to Inelastic collision

I know that if the collision was not elastic, some of the kinetic energy of the incident neutron wound be used up in some other process. But, I can't understand how I can figure out exactly how much. Even if I can calculate it, I don't know how to find the condition for the collision to go from...
19. ### How Do Inelastic Collisions Distribute Energy Between Heat and Sound?

In collisions that are inelastic or partially elastic, how can we predict how much of the energy lost to the surroundings becomes heat, and how much becomes sound? What determines that fraction?
20. ### I Inelastic vs. neutron capture

For neutron inelastic interaction, the nucleus de-excites by emitting gamma-rays or charged particles. However, for neutron capture, the nucleus de-excites by emitting gamma-rays only. Why does the nucleus in the neutron capture interaction de-excite by only emitting gamma-rays? why not by...
21. ### Elastic or inelastic collision?

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?
22. ### Inelastic collision problem: Bullet striking a wood block

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...
23. ### Angular Momentum in an Inelastic Collision

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...
24. ### Two-dimensional perfectly inelastic collision between two vehicles

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...
25. ### Determining position of an object after inelastic collision

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...
26. ### Initial velocity in an inelastic collision

Homework Statement A drunken driver crashes his car into a parked car that has its brakes set. The two cars move off together (perfectly inelastic collision) for 6.0 m. If the mass of the moving car is 1030 kg and the mass of the parked car is 1410 kg how fast was the first car traveling when...
27. ### Inelastic collision of ball and rod - rotation problem

Homework Statement A uniform rod of mass M and length l is hinged at the center. a particle of mass m and speed u sticks after hitting the end of the rod. find the angular velocity of the rod just after collision Homework Equations Energy conservation-0.5mu^2=0.5(m+M)v^2 Angular momentum...
28. ### Inelastic Collision: Finding Initial Angle

Homework Statement [/B] After a completely inelastic collision between two objects of equal mass, each having an initial speed of v, the two move off together with a speed of v/3. What is the angle between their initial directions.Homework Equations Conservation of momentum in both x and y...
29. ### Angular speed calculation after an inelastic collision

Homework Statement A disk [m=0.1 Kg; R=0.1 m] rotates about its center of mass [w=40 rad/s], on a smooth floor. A bar [m=0.1 Kg; lenght=R=0.1 m] moves on the floor with a speed Vb=4 m/s. At one point, the bar hits disk's edge in an inelastic collision, and they start rotating together. A)[Fixed...
30. ### Why is momentum conserved in elastic and inelastic collisions?

Why momentum conserved in elastic collision and inelastic collision? Please attach mathematical proof too
31. ### Energy Lost During Purely Inelastic Collisions

I'm curious about how the math comes out when you apply conservation of momentum to the theoretical problem of a moving object having a purely inelastic collision with another stationary object in a single dimension. Since the velocity of the combined object is entirely determined by the...
32. ### A and C collide with B inbetween; AB elastic, BC inelastic

Homework Statement Three bodies A,B,C on frictionless surface masses= 1 kg each, Positions at time 0: A is at x=0,. B is at x=1, C is at x=2 (unit is 1 meter). velocities at time 0: A : 1m/s (to the right), B = 0 m/s, C = -1 m/s Assume sizes are uniform, or just ignore the sizes in...
33. ### Inelastic collision with an inclined plane

Homework Statement A particle is thrown upward with speed 10√3 m/sec. It strikes an inclined surface. Collision between the particle and inclined plane is perfectly inelastic. What will be the maximum height attained by the particle from the ground. 2. Relevant information and equations In...
34. ### Inelastic 2D Collision with Vector Components

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...
35. ### Sequental elastic and inelastic collisions

Homework Statement A taxi car weighing 2000kg hits a stationary mini-van that has a mass of 2200kg. The taxi stops and the mini-van rolls and hits a stationary sports car with a mass of 1830kg. Their bumbers hit and they move together at 2.3m/s. What is the velocity of the taxi before the...
36. L

### Is my logic right for the answer to this inelastic car collision question?

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...
37. ### Zero momentum reference frame and an inelastic collision

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...
38. ### Inelastic collision, determine ratio KEf/KEi

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...
39. Y

### Inelastic Collision with a Mass attached to a Rod

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...
40. ### Inelastic collision and the sum of internal forces

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...
41. C

### Conservation of Linear Momentum and Covariance

Homework Statement Assume two masses m1' and m2' are moving in the positive x-direction with velocities v1' and v2' as measured by an observer in S' before a collision. After the collision, the two masses stick together and move with velocity v' in S'. Show that if an observer in S' finds...
42. J

### Question regarding inelastic/elastic collision.

Homework Statement [/B] Hi, I have a quick question regarding elastic and inelastic collisions. I preformed an experiment in my house with two large, heavy marbles. I rolled one horizontally towards a stationary one, recorded a video of the collision. I uploaded the video to Tracker software...
43. S

### Dropping a Block on a Spring with Completely Inelastic Collision

Homework Statement [/B] A block of mass, m, is dropped from height, h (above the plate), onto a plate of mass, M, which is attached to a spring with spring constant, k. The block sticks to the plate and the system starts to oscillate. What is the amplitude of the oscillations. Homework...
44. C

### Acceleration in One Dimensional Inelastic Collision

Homework Statement Two cars of 540 kg and 1400 kg collide head on while moving 80 km/h in opposite directions. After the collision, the automobiles remain locked together. Find the velocity of the wreck, the kinetic energy of the two-automobile system before and after the collision, and find...
45. ### Sphere sliding up a step - Inelastic Collision

Homework Statement A sphere of radius R is rolling without slipping with a velocity v and collides inelastically with a step of height h < R. ¿What is the minimum velocity for which the sphere will be over the step? Homework Equations Total kinetic energy (maybe)...
46. ### Collision with magnets -- Elastic or Inelastic?

In my experiment I am performing a collision with two carts with magnets attached with photogates and a labquest on an air track. I pushed the carts together and made sure that the carts did not come into contact. Based on my knowledge of collisions, I believed that the collision would have been...
47. ### Can total KE ever increase for inelastic collisions?

Homework Statement Is following statement True or False? For inelastic collusions, the total KE of colliding objects just after collision is less than the total KE just before collision. The answer is given as False with a mention saying: "This is normally true but in some cases it could...
48. ### Angular Momentum; rod & disk inelastic collision

Homework Statement The figure shows an overhead view of a 2.50-kg plastic rod of length 1.20 m on a table. One end of the rod is attached to the table, and the rod is free to pivot about this point without friction. A disk of mass 39.0 g slides toward the opposite end of the rod with an initial...
49. ### Heat energy in an inelastic collision

Homework Statement A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m/s. It hits the floor of the elevator (length of the elevator = 3 m) and does not rebound. What is the heat produced by the impact ? Would your answer be different if the...
50. ### Perfect Inelastic collision with string tension

Homework Statement A small wooden block with mass 0.800 kg is suspended from the lower end of a light cord that is 1.60 m long. The block is initially at rest. A bullet with mass 0.0132 kg is fired at the block with a horizontal velocity v-_i. The bullet strikes the block and becomes embedded...