3. Moments Flashcards
Define the term moment
The turning effect of a force around a point
Define the term couple
Pair of forces of equal size acting parallel to each other but in opposite directions
Define the term inertia
Resistance of an object to change of its motion
What affects a body’s inertia?
Its mass - the greater the mass, the greater its inertia
Define the term weight
The force experienced by a mass due to the gravitational field
What two conditions does the moment of a force depend on?
- Size of the force
2. How far the force is applied to the turning point
What is the equation to calculate moment?
M = F x d
M = Moment (Nm) F = Size of force (N) d = perpendicular distance between line of action of force and turning point (m)
State the principle of moments
In order for a body to be in equilibrium, the sum of the clockwise moments about any point must equal the sum of the anticlockwise moments about the same point
What happens when moments aren’t balanced?
The object will turn
What happens in moments in levers?
An effort force acts against a load force by means of a rigid object rotating around a pivot
Why are levers useful?
They increase the distance from the pivot a force is applied, so less force is needed to get the same moment / turning effect
Name 3 examples of levers?
- Spanners
- Wheelbarrows
- Scissors
Does a couple cause any resultant linear force?
No - it produces a turning effect
What does the size of the moment of a couple depend on?
- Size of the forces
2. Distance between the forces
Name an example of a couple
The forces when turning the handlebars of a bike
