Question

一雨滴从屋檐由静止自由下落，通过高为h=1.8 m的窗户的时间t=0.2 s.求屋檐离窗台的高度H.(取g=10 m/s²)

Answer 1

解析：雨滴落到窗户上沿H-h=gt₂²                                              ①

    雨滴落到窗台上H=g(t₁+0.2)²                                               ②

①-②得h=g(t₁²+0.4t₁+0.04-t₁²)= g(0.4t₁+0.04)=2t₁+0.2

    所以t₁== s=0.8 s

    将t₁代入②式H=×10×(0.8+0.2)² m=5 m.

答案：5 m