Effects of forces
Core concepts and learning points for this section:
Syllabus Points
Core
- 1.5.1.1 Know that forces may produce changes in the size and shape of an object
- 1.5.1.2 Sketch, plot and interpret load–extension graphs for an elastic solid and describe the associated experimental procedures
- 1.5.1.3 Determine the resultant of two or more forces acting along the same straight line
- 1.5.1.4 Know that an object either remains at rest or continues in a straight line at constant speed unless acted on by a resultant force
- 1.5.1.5 State that a resultant force may change the velocity of an object by changing its direction of motion or its speed
- 1.5.1.6 Describe solid friction as the force between two surfaces that may impede motion and produce heating
- 1.5.1.7 Know that friction (drag) acts on an object moving through a liquid
- 1.5.1.8 Know that friction (drag) acts on an object moving through a gas (e.g. air resistance)
Supplement
- 1.5.1.9 Define the spring constant as force per unit extension; recall and use the equation k = F / x
- 1.5.1.10 Define and use the term ‘limit of proportionality’ for a load–extension graph and identify this point on the graph (an understanding of the elastic limit is not required)
- 1.5.1.11 Recall and use the equation F = ma and know that the force and the acceleration are in the same direction
- 1.5.1.12 Describe, qualitatively, motion in a circular path due to a force perpendicular to the motion as: (a) speed increases if force increases, with mass and radius constant (b) radius decreases if force increases, with mass and speed constant (c) an increased mass requires an increased force to keep speed and radius constant 2 mv ( F = is not required) r continued www.cambridgeinternational.org/igcse 14 Subject content