A tortoise is just sinking in water of density `rho` The tortoise is assumed to be3 a hemisphere of radius `R`.
Find vertical thrust

Options

A. `rhogpiR^(3)`
B. `(1)/(3)rhogpiR^(3)`
C. `(2)/(3)rhogpiR^(3)`
D. 0

Answer

C

Explanation

Let the horizontal and vertical thrusts on the tortoise be `F_(h)` and `F_(v)` respectively
we know that `F_(h)=rhogy_(C)A_(v)` where `y_(C)=R` and `A_(v)=piR^(2)` This gives `F_(h)=rhogpiR^(3)` towards right
Similartly using the formula `F_(v)=rhoVg` where `V=` volume of the tortoise`=(2)/(3)piR^(3)` we have `F_(v)=(2)/(3)rhogpiR^(3)` (up)