Hydro150

Buoyancy in liquids

There are three formulae for calculating the buoyancy suffered by an immersed object:

1. Buoyancy =

(where V = the volume of liquid displaced and = the density of the liquid displaced).

2. Buoyancy in water =

, where W is the weight of the immersed object and s is its relative density.

3. Buoyancy in a liquid =

, where W is the weight of the immersed object, s is its relative density and s_l is the relative density of the liquid.

Okay so now there is only one thing to do,

Remember that the Forces Up = Forces Down

if something floats in water then B > W

but if it being held down B = W + T

If it rests on the bottom then the resultant, R = W - B

If it floats on top then

W = V_lp_lg

Common mistakes

• Mixing up density and relative density

• Mixing up pressure and thrust. Thrust is a kind of force.

• Confusing mass and weight. Weight is a force.

• Not being able to use the three methods of finding buoyancy.

One more section here