[填空题]
A stone is dropped from the roof of a building; 2.00 s after that, a zh1 ex kdzho8 -c,6)u gso*xl/second sto*l *lgqjeyn+ 7/mvgyab4+iyk/ls;*c ne is thrown straight down with an initial speed of 25.0 m/s and the two stones land at the s+clail *gkv*e/y+;g7jl n4y /*qm by same time.
(a) How long did it take the first stone to reach the ground? $t_1$ = s
(b) How high is the building? m
(c) What are the speeds of the two stones just before they hit the ground? #1 m/s #2 m/s