What is the Ratio of Speeds After a Noncentral Elastic Collision?

[EPhoenix]

Homework Statement

First sphere m=0.3 kg collide noncentraly and elasticaly with other sphere of m= 0.35 kg and transfer 79% of first sphere kinetic energy during that collision... u1 is not defined, u2 = 0 m/s

Ratio between speed after collision v1 : v2 = ??

Homework Equations

m1u1 + m2u2 = m1v1 + m2v2

The Attempt at a Solution

Tryied to make Ek = Ek1 + Ek2

m1u1 = m1v1 + m2v2

m2v2 = 0.79 m1u1
v2 = 0.677 u1

m1v1 = 0.21 m1u1

v1= 0.21 u1

so ratio would be

v1 : v2 = 0.21u1 : 0.677u1

so in conclusion

v1 : v2 = 1 : 3.224



But I don't know if it's false or right...

 

[thebigstar25]

hmmm , your solution doesn't seem logical enough to me .. for example why didnt you use the fact that k=0.mv^2 (or p^2/2m) ??notice what is the relationship between the kinetic energy and the velocity(or momentum) .. how would that change your calculations? .. please try again ..

 

[EPhoenix]

Yeah... I got right solution after applying it with kinetic formula...

Thx nevertheless :)