[填空题]
(a) If a volcano spews a 500-kg rock vertically upward a .7ngon 4ute k,ngy r,.dis(1hq2 gdw bv6stance of 500 m, what was its velocity when it lebv6d2(gswhq 1 ft the volcano? $\approx$ m/s
(b) If the volcano spews the equivalent of 1000 rocks of this size every minute, what is its power output? $\approx$ $a\times10^b$ W a = b =
