1
自屋檐到窗口的頂端用時間t
1/2g(t+0.25)^2-1/2gt^2=2
1/2g*0.5t+1/2g*0.0625=2
2.5t+0.3125=2
t=0.675
h=1/2gt^2=1/2*10*0.675^2≈2.28m
2
總時間為t
1/2gt^2-1/2g(t-4)^2=196
4*9.8*(t-4)=196
t=9s
h=1/2gt^2=1/2*9.8*9^2=396.9m
3
△h=[(vC^2-(3/5vC)^2]/(2g)=8vC^2/(25g)
80=8vC^2/(250)
vC=50m/s
H=vC^2/(2g)=50^2/(2*10)=125m