[填空题]
Two balls, of massespjb2 r1;s1kjpa*wm t;7n;,tw rg mkt2$m_A$ = 40g and $m_B$ = 60g are suspended as shown in Fig. 7–44. The lighter ball is pulled away to a 60$^{\circ} $ angle with the vertical and released.
(a) What is the velocity of the lighter ball before impact?$\approx$ m/s
(b) What is the velocity of each ball after the elastic collision?v'$_A$ $\approx$ m/s v'$_B$ $\approx$ m/s(Round to two decimal places)
(c) What will be the maximum height of each ball after the elastic collision? m