Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can state the definition p = mv, give its unit two ways (kg·m/s and N·s) and explain why momentum points the same way as velocity. (Guide: “The definition: p = mv”)
- I can explain why the momenta of a system can cancel while the kinetic energies cannot. (Guide: “Momentum of a system”)
- I can state the condition for the collision model and explain why only the states just before and just after are needed. (Guide: “Collisions and explosions as models”; Practice Q3)
- I can explain what makes an interaction an explosion, without needing fire or noise. (Guide: “Collisions and explosions as models”; Practice Q7(c))
Calculation
- I can calculate a momentum with the correct sign in one dimension from a position function. (Practice Q1)
- I can find the momentum of a two-object system in two dimensions by components, and give its size and direction with the correct quadrant. (Guide: Worked example 1; Practice Q4)
- I can differentiate x(t) or r(t) to find momentum as a function of time, and find when it is zero or greatest. (Guide: Worked example 2; Practice Q5)
- I can use K = p²/(2m) to move between kinetic energy and momentum and to predict factors of change. (Guide: “Momentum and kinetic energy”; Practice Q2, Q7)
Reasoning
- I can sketch a momentum–time graph from a position function and label zeros, turning points and end values. (Guide: Figure 2; Practice Q5(b))
- I can justify the collision model with numbers by comparing the velocity changes caused by internal and external forces during contact. (Guide: the bat-and-ball estimate; Practice Q6)
- I can explain why an external force that is negligible during an impact may still matter before or after it. (Practice Q6(d))
All ticked? Move on to Topic 4.2, Change in Momentum and Impulse, or return to the course roadmap.