[填空题]
Two students are asked to fin7lg -lf+dubkq4j 0t- ud the height of a particular building. u3f3drk81r vqThey take a stone to the roof of the building rkf38u dq31vrand drop it off, timing its fall. One student reports a fall time of 2.0 s, and the other, 2.9 s. How much difference does the difference in time make for the estimates of the building’s height? $m$
