From Problem $1-59$:

Sand grains, $S{G}_{\text{s}\text{a}\text{n}\text{d}}=2\mathrm{.}85,$ fall a short distance into a tank of water and have approximately spherical shape

with volume: $AA=\frac{}{6}{d}^3.$ Do the following:

A $-$ Compute the weight $($lb$)$ of a sand grain with diameter $d=0\mathrm{.}3mm.$ Weight $=$ volume $x$ specific weight

B $-$ Compute the weight $($lb$)$ of water displaced by a submerged sand grain $(d=0\mathrm{.}3mm)$

C $-$ Buoyant force is equal to the weight of fluid displaced by a floating or submerged body.

In this case, a sand grain is a submerged body and the buoyant force is your solution from part B$.$

Compute the submerged weight of a sand grain $($weight underwater$)$ considering the static force balance of

$(1)$ sand grain weight, $(2)$ buoyancy force, $(3)$ submerged weight.

Show your free$-$body diagram of force balance for the submerged sand grain.