Lesson Plan

• Describe momentum as a vector quantity and its relation to mass and velocity.
• Define resultant (net) force as the rate of change of momentum and express it with F = Δp/Δt.
• Apply the equation F = Δp/Δt to solve numerical problems involving changes in speed or direction.
• Distinguish between momentum and kinetic energy and identify common misconceptions.
• Evaluate when to use F = Δp/Δt versus F = ma for situations with varying mass.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with the ball example
• Calculators
• Momentum/force unit conversion chart
• Vector‑diagram handout
• Student response cards or sticky notes

Begin with a quick visual of a moving ball changing speed to spark curiosity about what “pushes” it. Review the previously learned formula p = mv and Newton’s second law F = ma. Explain that today’s success criteria are to define resultant force, derive its formula, and use it confidently in calculations.

1. Do‑now (5 min): Short quiz on p = mv and F = ma; students record answers on response cards.
2. Mini‑lecture (10 min): Introduce resultant force, derive F = Δp/Δt, and relate it to F = ma for constant mass.
3. Guided example (12 min): Work through the ball problem on the screen, students follow in their worksheets.
4. Paired activity (10 min): Calculate resultant force for a set of mass‑velocity‑time scenarios; discuss vector direction.
5. Mistake‑check (5 min): Present common errors; students correct statements using clicker responses.
6. Summary & exit ticket (3 min): Students write one correct statement and one question on a sticky note before leaving.

Recap that resultant force quantifies how quickly momentum changes and that the formula works for both constant‑mass and varying‑mass cases. Collect exit tickets to gauge understanding and assign a homework problem set requiring students to apply F = Δp/Δt to collisions and rocket‑thrust scenarios.