[填空题]
A stone is dropped from the roofq/ i)wygz ) vb8t.-mwk of afjrq t)on1q 8eg7 8lw7 building; 2.00 s after that, a second stone is thrown straight down with an i8o78gqq)l1j en w7 tfrnitial speed of 25.0 m/s and the two stones land at the 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
