Archimedes' Principle Archimedes’ principle states that an object submerged in a fluid at rest has?an upward buoyancy force (upthrust) equal to the weight of the fluid displaced by the object The o...
Upthrust Upthrust is a force which pushes upwards on an object submerged in a fluid i.e. liquids and gases Also known as buoyancy force, upthrust is due to the?difference in hydrostatic pressure?at...
Derivation of ?p = ρg?h Hydrostatic pressure?is the pressure that is exerted by a?fluid?at equilibrium at a given point within the fluid, due to the force of gravity The derivation for this equatio...
Pressure Pressure tells us how concentrated a force is, it is defined as the?force per unit area Pressure is equal to the force per unit area This equation tells us If a force is spread over a larg...
Density Density is the?mass per unit volume?of an object Objects made from low-density materials typically have a lower mass For example, a balloon is less dense than a small bar of lead despite oc...
Equilibrium A system is in equilibrium when all the forces are balanced. This means: There is?no?resultant force There is?no?resultant torque An object in equilibrium will therefore remain at rest,...
Couples A couple is a?pair?of forces that acts to produce?rotation?only Unlike moments of a single force, the moment of a couple doesn’t depend on a pivot, only on the perpendicular distance betwee...
What is a Moment? A moment is the?turning effect of a force Moments occur when forces cause objects to?rotate?about some pivot The moment of a force is given by Moment (N m) = Force (N) × perpendic...
Centre of Gravity The centre of gravity of an object is?the point at which the weight of the object may be considered to act For example, for a person standing upright, their centre of gravity is r...
