SIT. X: A right circular cone is $50mm$ in radius and $170mm$ high and weighs $2\mathrm{.}1N$ in air. It is placed to float in ethanol $($s$.$g$.=0\mathrm{.}79)$ with its vertex downward.

$68.$ Calculate the depth of submergence of the cone.

A$.82mm$

B$.93mm$

C$.86mm$

D$.103mm$

$69.$ How much force is required to push this cone vertex downward into the ethanol so that its base is exactly flushed at the surface?

A$.1\mathrm{.}07N$

B$.1\mathrm{.}35N$

C$.1\mathrm{.}75N$

D$.2\mathrm{.}27N$

$70.$ How much force will push the base $6\mathrm{.}5mm$ below the surface?

A$.1\mathrm{.}07N$

B$.1\mathrm{.}35N$

C$.1\mathrm{.}75N$

D$.2\mathrm{.}27N$