1. The problem statement, all variables and given/known data Mass A is moving towards mass B, which is stationary. Collision is elastic. After the collision both masses are mobing symmetrically to the initial direction of motion of mass A. What is the ratio of masses A and B if the angle between directions of motion of the masses is β? 2. Relevant equations Principle of conservation of momentum: -along the initial direction of A [tex]m_1v_1=m_1u_1cosβ+m_2u_2cosβ[/tex] -along the direction perpendicular to the one mentioned above [tex]m_1u_1sinβ=m_2u_2sinβ[/tex] Principle of conservationj of energy: [tex]m_1v_1^2=m_1u_1^2+m_2u_2^2[/tex] 3. The attempt at a solution Does the 'symmetrical motion' mean that [tex]u_1=u_2[/tex]? If so, then m1=m2, but the answer for this question is m1/m2=2.