Turning Forces And Centre Of Mass Flashcards
What is a moment?
The turning effect of a force
How do you find the moment of a force?
Force x perpendicular distance from the line of the action of the force of the pivot
What does a larger force cause?
A larger moment
What are moments measured in?
Newton metres
In the spanner example what does the nut act as?
The pivot as the spanner causes a turning effect or moment on the nut
Why would using a longer spanner exert a larger moment if the same force was used?
The distance from the pivot was greater
What do you need to do to get the maximum moment?
To push at right angles (perpendicular to the spanner)
Why does a right angle give the maximum tuning effect?
Any other angle means a smaller moment because the perpendicular distance between the line of action and the pivot is smaller
What is the centre of mass of on object?
The point at which the whole mass is concentrated
When will a freely suspended object spin until?
It’s centre of mass is vertically below the point of suspension
What does the objects weight do?
Acts at a distance from the pivot which creates a moment about the pivot
Why does It rest in the position that it does?
There’s no moment, the pivot is in line with the line of action of the force
How do you find the centre of mass of any flat shape?
Suspend the same and a plumb line (weight ) from the same point and wait until they’re stationary
Draw a line along the plumb line
Do the same thing again but suspend the shape from a different pivot point
The centre of mass is where your two lines cross
How do you find the centre of mass in symmetrical shapes?
Where the lines of symmetry cross
