Question

A 10m deep rectangular tank is filled with fresh water and open to the atmosphere.
On the bottom of the tank there are two drain plugs, one at the left and one at the right side.
The left drain plug is a flat circular disk. 50cm in diameter.
The right drain plug is a hemisphere, also 50cm in diameter.
Both plugs have chains attached to them and both are removed by lifting the chains.
Q1. What would be the upwards force required to lift the circular disk and allow water to escape?
Q2. What would be the upwards force required to lift the hemisphere and allow water to escape?

Answer 1

Answer:

77047.56 Newtons

Explanation:

Similar force acts on the two plugs since all horizontal components of force get cancelled out.

Force req for either of drain plugs

= 1000× 10× (9.81)× π× (0.5^2)

= 77047.56 Newtons