Turning Effect of Forces Flashcards
What is the moment of a force
The moment of a force is the product of the force and the perpendicular distance from the pivot to the line of action of the force
Formula to calculate moments, SI unit (vector quantity)
M = F x d
Moment = Force x distance
SI unit: Newton metre (Nm)
Principle of Moments
The principle of moments states that when an object is in rotational equilibrium, the sum of clockwise moments about a pivot is equal to the sum of anti-clockwise moments about the same pivot
Centre of gravity
The centre of gravity of an object is defined as the point through which its whole weight appears to act from any orientation of the object.
What is Stability
Stability refers to the ability of an object to return to its original position after it has been tilted slightly.
What are the 3 types of equilibriums
-Stable equilibrium
-Unstable equilibrium
-Neutral equilibrium
Stable equilibrium
-When an object is tilted slightly, the centre of gravity rises and then falls back again
-The line of action of weight lies inside the base area
-The anti-clockwise moment of its weight about the point of contact causes the object to return to its original position
Unstable equilibrium
-When an object is tilted slightly, the centre of gravity falls and continues to fall farther
-The line of action of weight lies outside the base area
-The clockwise moment of its weight about the point of contact causes the object to topple over
Neutral equilibrium
-The centre of gravity neither rises nor falls, it remains the same above the surface supporting it
-The lines of action of the two forces always coincide
-The moment of its weight about the contact point is zero, it stays in the position to which it is displaced
How to improve the stability of an object
-Wider base area
-Lower centre of gravity
