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 explain rotational inertia as resistance to changes in rotation, and compare it with inertial mass. (Guide: “Resistance to changes in rotation”)
- I can explain why the distance of mass from the axis matters more than the amount of mass. (Guide: “One small object: I = mr²”; Practice Q1)
- I can explain why one object has a different rotational inertia for each axis. (Guide: Worked example 1; Practice Q4)
- I can explain why a hoop’s rotational inertia is larger than that of a solid disk with equal mass and radius. (Guide: “Extended objects”; Practice Q2)
Skills
- I can calculate the rotational inertia of up to five point masses in a flat layout about a stated axis. (Guide: Worked example 1; Practice Q1, Q4)
- I can use Pythagoras to find a perpendicular distance from the axis before squaring it. (Guide: Worked example 1; Practice Q4)
- I can use the parallel axis theorem with a given I_cm and the total mass. (Guide: Worked example 2; Practice Q4, Q5)
- I can add a given extended-object inertia to point-mass contributions. (Guide: Worked example 3)
- I can linearise rotational inertia data by plotting I against r², and interpret the slope and intercept. (Practice Q6)
Reasoning
- I can locate the axis that gives the smallest rotational inertia and justify it with the centre of mass. (Guide: Figure 1; Practice Q3, Q5)
- I can predict the factor by which I changes when a mass is moved. (Guide: “One small object”; revision notes self-check)
- I can design an experiment that compares two rotational inertias using the same torque. (Guide: “How you could test this in the lab”; Practice Q7)
All ticked? Move on to Topic 5.5, Rotational Equilibrium and Newton’s First Law in Rotational Form, or return to the course roadmap.