Moments Flashcards
If there is an angle between a force and where it should be perpendicularly, what can you do to it?
Utilise trigonometry. If you are dragging it across the angle, use cosine, if you are not dragging it across the angle use sine.
What is a moment?
Turning forces around a pivot.
It is the turning effect on a body around a point.
How can we define a moment?
The moment of a force is the product of the magnitude of the force and the perpendicular distance of the line of action of the force from the pivot.
What is the formula for moments?
Moment = Force x distance
M = Fxd
Where force and distance are perpendicular.
What are moments measured in?
Newton-metres (Nm)
What do we do when denoting moments?
We give the direction, as to whether the moment is clockwise or anti-clockwise around the pivot.
What is a lamina?
A 2-dimensional plane on a closed surface.
Its mass is evenly distributed throughout its area.
Its the centre of mass is uniform with its geometric centre.
What is the sum of clockwise and anti-clockwise moments?
The Resultant Moment.
What can we say about the resultant moment of an object in equilibrium?
The sum of moments at any point is equal to zero.
What is a non-uniform body?
A body where the mass is not evenly distributed.
If it is rigid, it can be seen as acting at its centre of mass.
What do you often have to do with a non-uniform body?
Calculate its centre of mass.
