#vec P_1=m_1*vec v_1" momentum of " m_1" before collision" #
#vec P_2=m_2*v_2" momentum of " m_2 " before collision"#
#vec Sigma P_b=vec P_1+vec P_2" total momentum before collision"#
#Sigma vec P_b=m_1*vec v_1+m_2*vec v_2#
#Sigma vec P_b=3.16+1*0=48 " "kg*m/s#
#"post collision velocities :"#
#vec v_1^'=(2*Sigma vec P_b)/(m_1+m_2)-vec v_1#
#vec v_1^'=(2*48)/(3+1)-16#
#vec v_1^'=96/4-16#
#vec v_1^'=24-16=8" "m/s#
#vec v_2^'=(2*Sigma vec P_b)/(m_1+m_2)-vec v_2#
#vec v_2^'=(2*48)/(3+1)-0#
#vec v_2^'=96/4#
#vec v_2^'=24" "m/s#