Billiard ball collision at right angle

[Brite]

Homework Statement

Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Ball A is moving upward along the y-axis at 2.0 m/s and ball B is moving to the right along the x-axis with speed 3.7 m/s. After the collision (elastic), ball B is moving along the positive y axis. What is the final direction of ball A and what are their two speeds?

Homework Equations

m_Av_A + m_Bv_B = m_av'_A + m_Bv'_B
1/2m_Av_A² + 1/2m_Bv_B² = 1/2m_Av'_A² + 1/2m_Bv'_B²

The Attempt at a Solution

I know that because this is an elastic collision, momentum and kinetic energy are conserved. I think it's just that the two balls start on different axes is what's throwing me off.

 

[LowlyPion]

Homework Statement

Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Ball A is moving upward along the y-axis at 2.0 m/s and ball B is moving to the right along the x-axis with speed 3.7 m/s. After the collision (elastic), ball B is moving along the positive y axis. What is the final direction of ball A and what are their two speeds?

Homework Equations

m_Av_A + m_Bv_B = m_av'_A + m_Bv'_B
1/2m_Av_A² + 1/2m_Bv_B² = 1/2m_Av'_A² + 1/2m_Bv'_B²

The Attempt at a Solution

I know that because this is an elastic collision, momentum and kinetic energy are conserved. I think it's just that the two balls start on different axes is what's throwing me off.

Welcome to PF.

Indeed the 2 dimensions do make a difference. You will want to treat them separately.

Momentum in x is conserved
Momentum in y is conserved
KE is conserved.