Buoyancy and archimedes principle .

Buoyancy and archimedes principle .

1. Phenomenon responsible for buoyant force is called buoyancy

   • The magnitude of upthrust is always equal to the weight of the fluid displaced by the immersed part if the body

2. Liquids exert same pressure in all directions at a given depth causes upthrust

   • Density of a substance is defined as mass per unit volume

3. When a body is partially or wholly immersed in a fluid, an upward thrust acts on it

   • When a solid is immersed in a fluid it experiences an upthrust

4. Relative density of substance is compared with the density of water at 4°C

   • It can be defined as it is the ratio between the mass of a substance and the mass if an equal volume of water at 4°C
     • Sometimes also called as specific gravity
   • It has no units but is a pure number

5. Density in SI system = R.D×1000kgm¯³

   • Density of body is always greater than the density of the fluid

6. The center if buoyancy is the point where total upthrust due to the fluid displaced by the immersed part if the body acts

   • Weight of whole solid is equal to the weight of fluid displaced by immersed part of solid
   • Weight of solid acts vertically downward through the center of gravity, whereas upthrust acts vertically upward d through the center if buoyancy
   • In the floating position, the body is weightless and its apparent density and apparent weight is zero

7. The weight of the floating body should be equal to the weight of the fluid displaced by the immersed part of the body

   • The center of gravity of the body and center if buoyancy of the liquid displaced, must either coincide with each other or lie on the same vertical line

8. The vertical line passing through the new center of buoyancy, intersects the line joining the center of gravity and the original center of buoyancy at some point. This point is called metacentre

   • A body is in neutral equilibrium, if the center if gravity and metacentre if it coincide

9. Plimsoll lines indicate the safe limit for loading ship in sea water of some particular density

10. Upward force experienced by a body when partly or wholly immersed in a fluid is called upthrust

    • Magnitude of pressure exerted by a liquid increases with depth