[填空题]
A 2.30-m-long pole is bal (jn qo-qm ovh3/;r(wsanced vertically on its eb;2s (1zbhu m5u; hbw2u :wgptip. It starts to fall and its lower end does not slip. b5z(;;uw puge22:wmu h1 sbhbWhat will be the speed of the upper end of the pole just before it hits the ground? [Hint: Use conservation of energy.] $m/s$
