[填空题]
A ball of mass 0.440 kg moving east (+x direction) with a speed of cfoipri8 91 ywytjds8n+9 2.fy o;;fsclx )qq viz(+ 9tillides head-on with a 0.220-kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision?Let A represent the 0.440-kg ball, and B represent tiivqf9 lc;q+xt) z; s(he 0.220-kg ball. $v'_A$ m/s $v'_B$ m/s