A little physics here....

 t= 1.5 seconds
gravity= -9.1 m/s^2
initial velocity= 0 m/s

velocityfinal=velocityinitial-gravity*time
yfinal=yinitial+velocityinitial*time-gravity*time^2

So if Ranma drop the cat, she would impact the ground about 14.7
meters/second from a height of 22.1 meters.  I negleted air resistance and
the cat doing a tokyo shuffle.

Later fellow animeyers

Key wrote:

    Next to him was his cat, who was seated looking down at
the smooth white sand.  It shivered slightly.  Ranma
somehow felt it shiver.  "Scared of falling?"  Ranma
pushed his cat back away from the edge.  "Funny isn't it?
It takes roughly 1.5 seconds for you to fall from here."  He
leaned forwards slightly to get a better view of the ground.