Calculating Final Velocity with Inelastic Equations

[samreay]

Hey guys, I've been having a nasty problem in the construction of my physics engine, and it goes as follows.

When I have the mass and initial velocity of two objects (and Ill assume its a head on collision to simplify matters), how would you calculate the final velocity of both objects, when your given the fact that the collision is only a certain degree elastic, for example, one collision may only be 80% elastic, the other 20% of the energy is converted into heat.

Any help would be greatly appreciated.

 

[samreay]

Oh and after reviewing the Guidelines, should this be in the "Homework" type of area (even though it isn't related to schoolwork)?

If this is the wrong place, Ill move it as soon as I can figure out how.

 

[rock.freak667]

Well the coefficient of restitution would help...


$$e= \frac{v_2-v_1}{u_2-u_1}$$

 

[samreay]

So how would I use this coefficient? And does it change or become altered if the masses of the objects is different? Ill try sub-ing it into a few equations and see if there's a viable solution. Thank you for you help.

EDIT: I'm still having difficulties. After subbing that coefficient into the momentum formula and simplifying, I cannot get a viable answer. Was placing it in the momentum formula the wrong step?

 

[rock.freak667]

Read down the wikipedia page for http://en.wikipedia.org/wiki/Coefficient_of_restitution" , it has a formula for the final velocity. But you'd need to knwo the value of the COF and the inital velocities.

 

[samreay]

Ah okay, I've got it now.

Thank you for you help, I believe in my equations I had the system of equations as

V2 = CR(U2-U1) + V1

Where the in the brackets the It is actually (U1-U2).

Thanks

 

[rock.freak667]

Yeah it's supposed to be U1-U2, my mistake,it's the ratio of the of the relative velocities.