Archimedes Principle

When a body is wholly or partially immersed in a fluid it experiences an upthrust equal to the weight of the fluid displaced

Upthrust/Buoyant force

An upward force exerted by a fluid on an object immersed in it

Weight of displaced water...

....is always the same as the buoyant force

Buoyant force formula

The principle of floatation

When an object floats in a liquid the buoyant force/upthrust that acts on the object is equal to the weight of the object

If the weight of the object is greater than upthrust....

.....the object will sink

The forces acting on a sunk object

W (weight of object), F (upthrust) & R (normal reaction)

The forces acting on the object that is held by a string in water

W (weight of object), F (upthrust), T (tension of string)

Plimsoll Line

The Plimsoll line is an imaginary line marking the level at which a ship or boat floats in the water

Application of archimedes principle in submarine

To submerge, water is pumped into the ballast tank to increase the weight of the submarine