Partially inelastic collision

In summary, the two objects initially have 1/2 of the total kinetic energy and after collision, they have 1/2 of the final kinetic energy.
  • #1

Homework Statement

Two identical objects, each moving at 1m/s but in oposite directions collide partially inelastically in one dimension. Assume the final total kinetic energy is half the intial total value. Calculate the final speed of each object

Homework Equations

This is my main problem. My book is written by my teacher and meant to compliment his notes, and i missed two days of class because of illness. There is actually NOTHING in the book about partially inelastic collisions, only completely inelastic collisions. If its possible that the completely inelastic equation must be modified it is:

v' = (m1v1) + (m2v2)/(Total Mass)

The Attempt at a Solution

Dont even know where to begin...
Physics news on
  • #2
I believe what its saying that 2(1/2mV^2) is the initial energy of the system.

after collision its saying that final energy (sums) of the two particles is 1/2 this, in other words 1/2MV1^2 and 1/2MV2^2=1/2(2(1/2MV^2). Its likely that the v1 and v2 are the same from other considerations, only maybe in different directions??
  • #3
ok well, the answer is actually given...i just need to know how it is solved, the answer that it gives is:

.707m/s, .707m/s
  • #4
well from conservation of mo, one should be -0.707m/s, the .707 which can be derived from eqn as I posted above or at a glance knowing from cons of mo, and that final total energy =1/2 initial energy,
(1/2MVi^2)=2(1/2mvf^2). vf/vi=1/sqrt(2)
  • #5
vf/vi=1/sqrt(2) is what i should actually be using? What am i solving for in this equation...and the answer specifically states that they are both .707, one isn't negative.
  • #6
ok now i understand everything u said and i know how to do it now.

And i would like to add that this website is the most help i have ever received from any source. I've gone to study sessions at the math lounge at my college and sought help from other students in my class and this site beats all of that put together. Thanks so much for your help!

1. What is a partially inelastic collision?

A partially inelastic collision is a type of collision between two objects in which some kinetic energy is lost and the two objects stick together after impact. This is in contrast to a completely inelastic collision where the objects stick together and all kinetic energy is lost.

2. How is the coefficient of restitution calculated for a partially inelastic collision?

The coefficient of restitution, which measures the amount of kinetic energy lost during a collision, can be calculated for a partially inelastic collision using the formula e = (v2 - v1) / (u1 - u2), where v1 and v2 are the final velocities of the objects and u1 and u2 are the initial velocities.

3. What factors affect the outcome of a partially inelastic collision?

The outcome of a partially inelastic collision is affected by factors such as the masses and velocities of the objects, the angle of impact, and the materials of the objects. In general, a higher mass or lower velocity will result in a more inelastic collision.

4. How does a partially inelastic collision differ from an elastic collision?

In an elastic collision, the objects bounce off each other and no kinetic energy is lost. In a partially inelastic collision, some kinetic energy is lost and the objects stick together. Additionally, the coefficient of restitution for an elastic collision is 1, while it is less than 1 for a partially inelastic collision.

5. What are some real-life examples of partially inelastic collisions?

Some examples of partially inelastic collisions in everyday life include a car crash, a ball bouncing off a surface and not reaching its original height, and a person catching a ball and bringing it to a stop. In all of these cases, some kinetic energy is lost during the collision.

Suggested for: Partially inelastic collision