I have come across the classic problem of a body sliding on a frictionless hemisphere from rest. The problem is to find the height at which the body "falls off" from the hemisphere.
I have seen answers in this site and everybody seems to say that particle looses contact when Normal reaction, $N=0$. I don't understand why.
Since centripetal force is given by:
$F_c = mgcos\theta- N$ , (Where $\theta$ is angle from vertical)
And Conservation of mechanical energy results in :
$F_c= 2mg(1-cos\theta)$
as $\theta$ increases, clearly $F_c$ increases.
So if centripetal force increases, why does the body fall off? Also Normal reaction is pointing outward, so if it is decreasing doesn't it support the circular motion?( Since circular motion is supported by inward forces) So if $N=0$ , why does the body stop circular motion, as if $F_c=0$?