Scalars, vectors and kinematics
- Scalars (magnitude only) vs vectors (magnitude + direction); resolve into components (F cos theta, F sin theta) and combine by scale drawing or Pythagoras.
- suvat for constant acceleration; motion graphs (displacement-time gradient = velocity; velocity-time gradient = acceleration, area = displacement).
- Projectiles: horizontal and vertical motion are independent; vertical acceleration g, horizontal velocity constant.
Newton's laws and momentum
- N1 (constant velocity unless a resultant force acts), N2 (F = ma = rate of change of momentum), N3 (equal and opposite).
- Momentum p = mv; conserved in collisions/explosions; impulse = Ft = change in momentum (area under a force-time graph).
Work, energy and power
- Work = Fs cos theta; KE = 1/2 mv^2; GPE = mgh; conservation of energy; power = work/time = Fv; efficiency = useful/total x 100%.
Resolve vectors before applying suvat or Newton's laws, and treat projectile motion as two independent directions.
Diagram
Define system
Draw diagram
Resolve/choose equation
Substitute SI units
Interpret direction/gradient/area
Model assumptions
Calculation
Unit check
Physical meaning