✔ 最佳答案
設石A,B,C開始下跌的地方是高度為 0,設初速度為 0。
h = (V₀)(t) - (1/2)gt²
ha = (0)(t) - (1/2)gt²
ha = - (1/2)gt²
hb = - (1/2)g(t-1)²
hc = - (1/2)g(t-2)²
hb-hc = - (1/2)g[(t-1)² - (t-2)²]
= - (1/2)g[t²-2t+1-(t²-4t+4)]
= - (1/2)g[t²-2t+1-t²+4t-4]
= - (1/2)g[2t-3]
|hb-hc| = (1/2)g[2t-3]
B,C兩石相距 = (1/2)g[2t-3]