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 that the net external force on a system equals dp/dt, and explain why internal forces cannot change the system’s momentum. (Guide: “Net force is the rate of change of momentum”)
- I can explain why impulse is a vector that points the way of the net force, not the way of motion. (Guide: Worked example 2)
- I can explain why a longer interaction time lowers the average force for the same change in momentum. (Guide: “The impulse–momentum theorem”)
Calculation
- I can calculate impulse from a constant force and use it to find a final velocity. (Practice Q1)
- I can integrate a force given as a function of time to find the impulse, without using a single value of the force as the average. (Guide: Worked example 1; Practice Q2, Q4)
- I can find Δp with signed velocities, in one dimension and by components in two. (Guide: Worked example 2; Practice Q6(b))
- I can find the net force from the slope of a momentum–time graph. (Guide: “Two graph rules”; Practice Q3)
- I can find impulse from force–sensor data by the trapezium rule or by counting squares. (Practice Q6(a))
Reasoning
- I can derive F_net = ma from F_net = dp/dt for constant mass, and F = v dm/dt for mass added at constant velocity, stating the assumption about the added mass. (Guide: “Newton’s second law as a special case”; Practice Q7)
- I can derive a symbolic final speed from a time-varying force and compare it with another scenario by a ratio. (Practice Q5)
- I can sketch a momentum–time graph from a force–time graph, showing where it is steepest and where it is flat. (Guide: Figure 1; Practice Q5(d), Q6(e))
- I can judge whether experimental data support the impulse–momentum theorem, with a numerical comparison. (Practice Q6(c))
All ticked? Move on to Topic 4.3, Conservation of Linear Momentum, or return to the course roadmap.