[填空题]
A rock is dropped from a sea cliff, and the uni )dv; ox/97e:fcxcsound of it strikinghxjii/( qqv)nyz2 anbsmk:(f8 / i1n 9 the ocean is heard 5.2 s(z 9:jsn k2bx)a/i (/q m1vnq8ihnify later. If the speed of sound is $340 \; m/s$, how high is the cliff? $m$
