Question

1) The neck and bottom of a bottle are 2 cm and 10 cm in diameter 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 ?

2) Name the law/princple you have used to find this force.

Answer 1

Diameter of the neck is = 2 cm = 0.02 m

So, area of cross-section of the neck is, a = Ï€d ² /4 = 0.000314 m ²

Diameter of the bottom is = 10 cm = 0.1 m

So, area of cross-section of the bottom is, A = Ï€d ² /4 = 0.00785 m ²

Force applied to the cork, f = 1.2 kgf

Let F be the force at the bottom, so,

F/A = f/a

=> F = (f/a)A = (1.2/0.000314)(0.00785) = 30 kgf

principle used - Psacal's Law