[填空题]
A stone is thrown vertically m:*ysnxm zx 1q 3/nnko m/x9pz:x9ch4upward with a spevuxe 1oan-9u ;5jbv5uu ig- /med of 12.0 m/s from the edge of a cliff 70.0 u u;j5ugi/ 1v-n5emoux-ba v9m high (Fig. 2–34).
(a) How much later does it reach the bottom of the cliff? t = s
(b) What is its speed just before hitting? m/s
(c) What total distance did it travel? m