Motion — Newton's laws and momentum
VCE Physics · Motion & Newton's laws · 6 flashcards, free to study.
Foundations for Unit 3 motion. Includes the airbag / crumple-zone reasoning examiners love.
- Newton's first law
- Object remains at rest or in uniform motion unless acted on by a net external force.
- Newton's second law
- F_net = ma (force in N, mass in kg, acceleration in m/s²).
- Define impulse
- J = FΔt = Δp (change in momentum). Units N·s = kg·m/s.
- Conservation of momentum — when does it apply?
- Closed, isolated system (no external net force) — momentum before = momentum after.
- Difference between elastic and inelastic collisions
- Elastic: KE conserved. Inelastic: KE not conserved (some lost to heat, sound, deformation).
- How does increasing collision time reduce force?
- For the same Δp, longer Δt → smaller F (crumple zones, airbags).