Turning effects of forces Flashcards
Define moment.
The moment of a force is the product of the force F and the perpendicular distance d from the pivot to the line of action of the force.
What is the formula for a moment?
moment [Newton metre(Nm)] = F[N] x d[m]
What is a pivot? (layman terms)
It is the point at which an object rotates about.
What are the two conditions for a system to be in equilibrium?
- The forces acting on it must be balanced; the resultant is 0.
- The total clockwise and anticlockwise moments are balanced; the resultant moment about the pivot is 0.
What is the difference between translational and rotational equilibrium?
Translational equilibrium means that the forces are balanced and there is no resultant force. This means that the object can be moving but there will be no acceleration.
Rotational equilibrium means that the moments are balanced and the net moment is 0. This means that the object does not move at all.
State the principal of moments.
The prinicple of moments states that when a body is balanced, the sum of clockwise moments is equal to the sum of anti-clockwise moments about the same pivot.
Define centre of gravity.
The centre of gravity of any object is defined as the point through which its whole weight appears to act. For regularly-shaped objects, the centre of gravity is at the geometrical centre.
