Question

井口每隔1S有一粒石头落下,第5颗开始落时,第一颗刚好落下,

Answer 1

T=4s,

H=(g*T*T)/2=80m

T2=2s

T3=3s

H2=(g*T2*T2)/2=20m

H3=(g*T3*T3)/2=45m

△H=15m