A rectangular surface $3\text{'}4\text{'},$ has the lower $3$ edge horizontal and $6\text{'}$ below a free oil surface $($sp$.$ gr$.0\mathrm{.}8).$ The surface inclination is $300$ with the horizontal. The force on one side of the surface is $($where$,$ y $=$ specific weight of water$)$

$39\mathrm{.}6$y

$48$y

$49\mathrm{.}2$y

$58$y