Elastic Glancing Collision?

Question

Two objects of masses m and 3m are moving towards each other along the x-axis with the same initial speed of v. The object with mass m is travelling to the left, and the object with mass 3m is traveling to the right. They undergo an elastic glancing collision such that m is moving downward after the collision at right angles from its initial direction. (a) find the final speeds of the two objects (b) What is the angle at which the object with mass 3m is scattered?

Answer 1

Conservation of momentum in two dimensions:

The initial x momentum is

mv - 3mv

The final x momentum is ( 3m ) vx
where vx is the x velocity of the 3m mass.
So conservation of momentum on this axis says that

mv - 3mv = 3m vx

The initial y momentum is zero

The final y momentum is 0 = ( m ) ( -vy ) + ( 3m ) ( 1/3 vy )
where vy is the magnitude of the y velocity of mass m
(and 1/3 vy the velocity of mass 3m).

Answer 2

If this is declared to be elastic, ability is conserved besides as momentum. (a million/2)M(x)[V(i)^2} = (a million/2)M(x)[V(f)^2} + (a million/2)M(y)[V(y)^2) (a million/2)(4.0)(6.0)^2 = (a million/2)4.0{[3.0)^2] + (a million/2)(2.0)[V(y)^2] 2(36.)-2[9.0)] = V(y)^2 = seventy two-18= fifty 4. V(y) = SQRT (fifty 4) so i are not getting 4.2m/s the two.