watch:

https://youtu.be/qb40J4N1fa4

question:

At 4:40 > its stated that a(t)2 + y(t)2 = 52 is true at all points of time for the ladder problem. Is that accounting for when the ladder is perfectly parallel with the wall or completely flat on the ground creating a 0 along the x or y axis. Or is it merely true for the times when the ladder is only in motion and creating an angle as displayed