Forces definitions Flashcards
Hooke’s law
The extension of a body is proportional to the applied load if the limit of proportionality is not exceeded
Density
Mass per unit volume
Pressure
Force per unit area
Upthrust
Vertical upward force exerted on a body by a fluid when it is fully or partially submerged in the fluid due to the difference in fluid pressure
Archimedes Principle
Upthrust on a body in a fluid is equal to the weight of the fluid displaced by the body
Principle of floatation
For an object floating in equilibrium, the upthrust is equal in magnitude and opposite in direction to the weight of the object
Moment of a force about an axis
The moment of a force about an axis is defined as the product of the force and the perpendicular distance of the line of action of the force from the axis
Couple
A pair of equal and opposite forces whose lines of actions do not coincide
Torque of a couple
The product of the magnitude of one of the forces and the perpendicular distance between the forces
Centre of gravity
The point at which its whole weight appears to act
Static equilibrium
Translation eq: The total resultant forces acting on the object must be zero;
Rotational eq / Principle of moments: For a body in rotational equilibrium, the sum of all the clockwise moments about any axis must be equal to the sum of all the anticlockwise moments about the same axis