Understanding how a projectile that moves in a parabolic path

[tatiana]

I need help understanding how a projectile that moves in a parabolic path can have a point where a-> is parallel to v-> or perpendictular to v->
Is this meaning that the lines tanget to the path are perpendicular or the actuall path?
And i would think that both parallel and perpendicluar are ppossible, yes?

 

[pallidin]

Why the unusual thread title?
Looks like a password :)

 

[Redbelly98]

I need help understanding how a projectile that moves in a parabolic path can have a point where a-> is parallel to v-> or perpendictular to v->
Is this meaning that the lines tanget to the path are perpendicular or the actuall path?
And i would think that both parallel and perpendicluar are ppossible, yes?

Well, a is always pointing downard. So what would it mean for v to be either parallel or perpendicular to that?