Because △ABC is an isosceles triangle
So point d is the midpoint of the bottom BC.
Bd = 4cm
cos∠ABD=BD/AB=4/5
The passing point A is AE⊥AB, and the passing point BC is E.
AB/BE=cos∠ABD=4/5
BE = 25/4 = 6.25
BE/0.25=6.25/0.25=25(s)
CE=BC-BE=8-6.25= 1.75cm
CE/0.25= 1.75/0.25=7(s)
According to symmetry, we know that point A is the intersection of AF⊥AC and BC at point F.
BF=CE
When P moves to point F, it passes through 7s,AF⊥AC.
When P moves to point E, after 25s,AE⊥AB.