Originally Posted by

**free_to_fly** The question that I'm stuck on is:

A bowl is made from a smooth spherical shell of radius r by cutting away the part which is more that $\displaystyle \

\frac{1}{3}r

\$ above the horizontal plane through the centre. A marble is projected from the lowest point of the bowl with speed u. Show that in the subsquent motion the marble will leave the bowl and not fall back into it provided:

$\displaystyle \

u^2 > \frac{{17gr}}{3}

\$

I don't know where to being, in fact, I'm not even 100% sure of what the question's saying, so any help would be greatly qppreciated.