Physics collision problem .. . . elastic collision?

Question

A red air track glider of mass 228 g moving with initial velocity +5.60 cm/s collides elastically with a blue air track glider of the same mass moving with an initial velocity of -37.90 cm/s. What will the red glider's velocity be, in cm/s, after the collision? Please give your answer to TWO DECIMAL PLACES. Don't forget the +/- sign! HINT: Do all of the algebra first, before you do any calculations with numbers. If you calculate with the numbers first, you are likely to get an answer that is not quite correct.

Answer 1

Momentum before collision=Momentum after collision

Momentum of red before collision=mv=m*(+5.60)
Momentum of blue before collision=mv=m*(-37.90)
Total Momentum before collision=m*(-32.3)

Momentum of red after collision=mv=m*x
Momentum of blue after collision=0
Total Momentum after collision =m*x

m*(-32.3)=m*x
x=-32.3cm/s

Answer 2

sorry but i cant explain with values coz it will take too much time to calculate . i will only tell u the procedure . us mgh = change in kinetic energy of ball for 2 positions of the , horizontal and vertical . so u can get velocity of ball just before striking . now use conservation momentum . so now u will hav one eqn. with 2 unknwns . now as collision is elastic total energy before and after the collision dame . so k.e. before collision = k.e. after collision [i.e. ke of both the bodies]. so now u will jav amother eqn. with same 2 unkwns as above . solve these 2 eqns. amf u will get required ans.

Answer 3

Go here: http://en.wikipedia.org/wiki/Elastic_collision

You just need the proper equations. Rearrange them to solve for the final velocity of the glider in question and THEN plug your numners in.

I'd convert from cm/s to m/s and grams to kg's because I find if you always use standard convention it's easier to keep track of units.