How Do You Calculate Speed After a Partially Inelastic Collision?

[jjf5122]

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...

 

[denverdoc]

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??

 

[jjf5122]

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

 

[denverdoc]

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)

 

[jjf5122]

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.

 

[jjf5122]

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!