💥 4. Momentum & Collisions

Momentum = mass × velocity (p = mv). Momentum is a vector quantity.

The principle of conservation of momentum: total momentum before = total momentum after.

Impulse = force × time = change in momentum (Ft = Δp).

Elastic collisions: kinetic energy is conserved.

Inelastic collisions: kinetic energy is not conserved.

Perfectly inelastic collisions: objects stick together after collision.

The coefficient of restitution e = relative speed of separation / relative speed of approach.