Question

(i) The diameter of neck and bottom of a bottle are 2 cm and 10 cm, respectively. The bottle is completely filled with oil. If the cork in the neck is pressed in with a force of 1.2 kgf, what force is exerted on the bottom of the bottle?

(ii) Name the law/principle you have used to find the force in part (a).

Answer 1

(i) Diameter of the neck of the bottle , d₁ = 2 cm
Diameter of the bottom of the bottle , d₂ = 10 cm
Force on the cork in the neck , F₁ = 1.2 kgf
Force on the bottom be F₂
By the principle of hydraulic machine ,
Pressure on neck = pressure on bottom
or , `F_1/A_1 = F_2/A_2` 

or , `1.2/(pi(d_1"/"2)^2)` = `F_2/(pi(d_2"/"2)^2)`

or , `F_2 = 1.2/(2)^2 xx (10)^2 = 30` kgf

(ii) Pascal's law has been used to find the force .