[填空题]
A 2.30-m-long pole isq*aw:bg4;fbe:9 fnn j balanced vertically on its ti r/od1 4ov8xjep. It starts to fall and its lower end does not slip. What will be the speed of the upvod48x/ jo r1eper end of the pole just before it hits the ground? [Hint: Use conservation of energy.] $m/s$