1
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 1 Part 2
, 2
Turning Effect of Forces
1 Describe the moment of a force as a measure of its turning effect and give everyday examples
2 Define the moment of a force as moment = force × perpendicular distance from the pivot; recall and use
this equation
3 Apply the principle of moments to situations with one force each side of the pivot, including balancing of a beam
4 State that, when there is no resultant force and no resultant moment, an object is in equilibrium
5 Apply the principle of moments to other situations, including those with more than one force each side of the pivot
6 Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium
7 State what is meant by centre of gravity
8 Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina
9 Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects
Moments
Defining and calculating moment: moment = force × perpendicular distance from the pivot (Ncm or Nm)
Moments have two directions: clockwise and anticlockwise
If a force is at the pivot there is no moment.
Equilibrium: there is no resultant force and no resultant moment
Applying equilibrium: clockwise moment = anticlockwise moment
Center of Gravity
Defining centre of gravity: a point in an object where weight is considered to act
For regular shapes, centre of gravity is in the geometrical center of the object.
For irregular shapes, centre of gravity is near the heavier portion of the object.
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 1 Part 2
, 2
Turning Effect of Forces
1 Describe the moment of a force as a measure of its turning effect and give everyday examples
2 Define the moment of a force as moment = force × perpendicular distance from the pivot; recall and use
this equation
3 Apply the principle of moments to situations with one force each side of the pivot, including balancing of a beam
4 State that, when there is no resultant force and no resultant moment, an object is in equilibrium
5 Apply the principle of moments to other situations, including those with more than one force each side of the pivot
6 Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium
7 State what is meant by centre of gravity
8 Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina
9 Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects
Moments
Defining and calculating moment: moment = force × perpendicular distance from the pivot (Ncm or Nm)
Moments have two directions: clockwise and anticlockwise
If a force is at the pivot there is no moment.
Equilibrium: there is no resultant force and no resultant moment
Applying equilibrium: clockwise moment = anticlockwise moment
Center of Gravity
Defining centre of gravity: a point in an object where weight is considered to act
For regular shapes, centre of gravity is in the geometrical center of the object.
For irregular shapes, centre of gravity is near the heavier portion of the object.
