# Forces and Newton's Laws

AS Level

• Understand the concept of a force; understand and use 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
• 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 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)
• Understand and use Newton’s third law; equilibrium of forces on a particle and motion in a straight line (restricted to forces in two perpendicular directions or simple cases of forces given as 2-D vectors); application to problems involving smooth pulleys and connected particles

A Level

• extend to situations where forces need to be resolved (restricted to 2 dimensions)
• resolving forces in 2 dimensions; equilibrium of a particle under coplanar forces
• Understand and use addition of forces; resultant forces; 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