Momentum and Impulse Topic Review summary

Key learning points

• Impulse $=\\int F\\,dt=$ change in momentum $mv-mu$.
• For a system with no external impulse, total momentum is conserved.
• Take a clear positive direction; opposite velocities get opposite signs.
• Impulse in a string/rod along its length at a jerk.
• Units: momentum $\\mathrm{kg\\,m\\,s}^{-1}$; impulse $\\mathrm{N\\,s}$.

Worked example 1 — Impulse

Mass 2 kg speed 3→7 m/s same direction. Impulse?

Working

$m(v-u)$.

Worked example 2 — Conserve

When is momentum conserved?

Working

Internal impulses cancel in pairs.

Worked example 3 — Practice point 1

Impulse $=\\\\int F\\\\,dt=$ change in momentum $mv-mu$.

Working

Attempt without notes, then check the answers PDF.

Worked example 4 — Practice point 2

Apply this idea from the Topic Review: For a system with no external impulse, total momentum is conserved.

Working

Attempt without notes, then check the answers PDF.

Scaffolded Learning Sheet and answers (PDFs)

This page is a short, searchable overview for revision and search engines. Use the Scaffolded Learning Sheet first, then the Answers PDF for a full written solution. The printable PDFs remain the main classroom resource.