[填空题]
A ball of mass m makes a head-on elastic collision with a second tx;; io ;o++fagt8a yaball dsr fuk 3.a 5m)g /dl/8apnrm)(at rest) and rebounds in the opposd .k5m8srdm /rn fagu/lpa ))3ite direction with a speed equal to one-fourth its original speed. What is the mass of the second ball? $m_B$ = $m_A$(Round to two decimal places)
