Define centre of mass
The centre of mass is the point in which a force acting through it would cause acceleration but no rotation
Define centre of gravity
The point from which the weight of the object acts from
Define the principle of moments
For a body in rotational equilibrium anti-clockwise moments round a point equal clockwise moment about the same point.
A couple definition
Two force that are parallel but all no along different lines of action.
What is torque?
Force exerted over unit area
Pressure exerted by a colour of fluid
The up thrust exerted on a body immersed in a cloud is equal to the weight of fluid distances