Understand the concept of a force; understand and use Newton’s first law.

Normal reaction, tension, thrust or compression, resistance.

Forces Newton's first law

Understand and use Newton’s second law for motion in a straight line (restricted to forces in two perpendicular directions or simple cases of forces given as 2-D vectors); extend to situations where forces need to be resolved (restricted to 2 dimensions).

Problems will involve motion in a straight line with constant acceleration in scalar form, where the forces act either parallel or perpendicular to the motion.

Extend to problems where forces need to be resolved, e.g. a particle moving on an inclined plane.

Problems may involve motion in a straight line with constant acceleration in vector form, where the forces are given in \(\bold{i} - \bold{j}\) form or as column vectors.

Newton's second law for motion in a straight line

Understand and use weight and motion in a straight line under gravity; gravitational acceleration, \(g\), and its value in S.I. units to varying degrees of accuracy.

The default value of \(g\) will be \(9.8 m~s^{-2}\) but some questions may specify another value, e.g. \(g = 10 m~s^{-2}\).

The inverse square law for gravitation is not required and \(g\) may be assumed to be constant, but students should be aware that \(g\) is not a universal constant but depends on location.

Weight and motion in a straight line under gravity

Understand and use Newton’s third law; equilibrium of forces on a particle and motion in a straight line; application to problems involving smooth pulleys and connected particles; resolving forces in 2 dimensions; equilibrium of a particle under coplanar forces.

Connected particle problems could include problems with particles in contact e.g. lift problems.

Problems may be set where forces need to be resolved, e.g. at least one of the particles is moving on an inclined plane.

Newton's third law Equilibrium of forces on a particle Smooth pulleys Connected particles

Understand and use addition of forces; resultant forces; dynamics for motion in a plane.

Students may be required to resolve a vector into two components or use a vector diagram, e.g. problems involving two or more forces, given in magnitude-direction form.

Resultant forces and dynamics for motion in a plane

Understand and use the \(F ≤ μR\) model for friction; coefficient of friction; motion of a body on a rough surface; limiting friction and statics.

An understanding of \(F = μR\) when a particle is moving.

An understanding of \(F ≤ μR\) in a situation of equilibrium.

Friction