Physics further turning forces

Physics revision further-Turning forces

Moments

• It is the effect of a turning force
• To increase the moment
  • Increase the size of the force
  • Increase the distance between the point of force exertion and the pivot.
• The weight being moved is called the load
• The force being applied is called the effort
• Moment is worked out using the equation
  • Moment = force x distance form force to pivot.

(Newton metre= Newtons x metres)

Centre of mass

• The COM is the point were all weight of an object acts from
• It is the point were all an objects mass may be thought to concentrate.
• An suspended object will come to rest with it’s COM directly below it’s point of suspension.
  • When it is still this is called equilibrium.
• To find the COM of a symmetrical object you just find were the lines cross.

Moments in balance

• For an object to be balanced and stationary then the force of the clockwise and anticlockwise moments must be equal.
  • A good example is a see-saw

Stability           

·        The base is the width of the bottom of the object

·        An object will fall over when it’s COM acts outside it’s base

•  
  • A good way to visulise the COM acting is to imagaine a line between it and the centre of the earth.
  • So when that line falls outside the base the object will fall over
• Examples of objects and basses
  • Busses have to be tested to make sure they will not fall over.
  • Tractors have wide bases so they can travel over bumpy land
  • High chairs have to have a wide base so wiggly children will not fall out.

Circular motions

• For an object moving a circle…