turning forces- moments
- The turning effect of a force is called the moment.
- a moment can increased by increasing the size of the force and increasing the distance from the pivot/centre point
- moments are measure in newton metres: Nm
moment = force x perpendicular distance from where the force is being applied.
turning forces-centre of mass
- the centre of mass of an object is where the mass is thought to be most concentrated.
- an object that is being suspended will always return to a point where its centre of mass is directly below the point of suspension. the object is then at equilibrium meaning there is no turning force.
- the centre of mass for a symmetrical object run along it's lines of symmetry.
turning forces- balancing moments
for an object to be in equilibrium:
the sum of all the clockwise moments about any point
the sum of all anticlockwise moments about that point.
(force1 x distance 1) = (force 2 x distance 2)
to increase stability:
- increasing the width of the objects base
- lowering the centre of mass
an object will topple over if its line of action of its weight acts outside its base
(imagine a line along the centre of mass is acting straight down and this line goes outside of the base of an objectas the object tilts.)
turning forces-circular motion
when an object moves around a circle at a constant speed:
- the object accelerates continuously towards the centre of the circle.