Forces

2026 Syllabus Objectives

Effects of Forces (1.5.1)

Core:

1. Know that forces may produce changes in the size and shape of an object
2. Sketch, plot and interpret load-extension graphs for an elastic solid and describe the associated experimental procedures
3. Determine the resultant of two or more forces acting along the same straight line
4. Know that an object either remains at rest or continues in a straight line at constant speed unless acted on by a resultant force
5. State that a resultant force may change the velocity of an object by changing its direction of motion or its speed
6. Describe solid friction as the force between two surfaces that may impede motion and produce heating
7. Know that friction (drag) acts on an object moving through a liquid
8. Know that friction (drag) acts on an object moving through a gas (e.g. air resistance)

Supplement: 9. Define the spring constant as force per unit extension; recall and use the equation k = F/x 10. Define and use the term 'limit of proportionality' for a load-extension graph and identify this point on the graph 11. Recall and use the equation F = ma and know that the force and the acceleration are in the same direction 12. Describe, qualitatively, motion in a circular path due to a force perpendicular to the motion

Turning Effect of Forces (1.5.2)

Core:

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

Supplement: 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

Centre of Gravity (1.5.3)

Core:

1. State what is meant by centre of gravity
2. Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina
3. Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects

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