[问答题]
If air resistance is neglectc5),p y0 n0we nfm,ruxed, show (algebraically) that a ball thrown vertica- q,m+5ayz6(xjao2om:a v ,mgo1pzx klly u kmoomqy2a,,z+zo (mp:vagx6-a1 x5jpward with a speed $v_0$ will have the same speed, $v_0$, when it comes back down to the starting point.
