4.1 Forces and equilibrium

Identify the forces acting in a given situation.

For example, by drawing a force diagram.

Taught in: Forces and force diagrams · 4 questions

Understand the vector nature of force, and find and use components and resultants.

Calculations are always required, rather than approximate solutions by scale drawing.

Taught in: Components and resultants of forces · 4 questions

Use the principle that, when a particle is in equilibrium, the vector sum of the forces acting on it is zero, or equivalently that the sum of the components in any direction is zero.

Solutions by resolving are usually expected, but equivalent methods (e.g. triangle of forces, Lami's Theorem, where suitable) are also acceptable; these other methods are not required knowledge and will not be referred to in questions.

Taught in: Equilibrium: when the forces cancel out · 6 questions

Understand that a contact force between two surfaces can be represented by two components, the normal component and the frictional component.

Taught in: Contact forces and smooth surfaces · 4 questions

Use the model of a 'smooth' contact, and understand the limitations of this model.

Taught in: Contact forces and smooth surfaces · 1 question

Understand the concepts of limiting friction and limiting equilibrium, recall the definition of coefficient of friction, and use the relationship F = μR or F ≤ μR, as appropriate.

Questions may use terminology such as 'about to slip' to mean 'in limiting equilibrium'.

Taught in: Friction, limiting equilibrium and Newton's third law · 4 questions