1
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 1 Part 2
Mohammed Ali
[Physics with Mo Ali]
Cambridge IGCSE Physics Revision Guide by Mo Ali – 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 by Mo Ali – Unit 1 – Part 2
Cambridge IGCSE
Physics
Revision Guide 2024
Unit 1 Part 2
Mohammed Ali
[Physics with Mo Ali]
Cambridge IGCSE Physics Revision Guide by Mo Ali – 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 by Mo Ali – Unit 1 – Part 2
