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, using Newton’s third law, why internal forces give equal and opposite impulses and so cannot change a system’s total momentum. (Guide: “Why internal forces cancel”)
- I can explain that momentum is conserved in every interaction, while a chosen system’s momentum changes if a net external force acts on it. (Guide: “Choosing the system”; Practice Q2)
- I can choose a system so that unknown forces are internal, and say which components of its momentum are conserved. (Guide: sandbag example; Practice Q6)
- I can explain why we compare states just before and just after a collision or explosion. (Guide: “Collisions and explosions”; Practice Q5(e))
Calculation
- I can find the total momentum and the center-of-mass velocity of a system, using signed velocities. (Guide: “Total momentum and the center of mass”; Practice Q1)
- I can use conservation of momentum in one dimension to find an unknown velocity after an explosion or recoil. (Guide: Worked example 1; Practice Q3)
- I can conserve the x- and y-components separately to find a velocity in two dimensions, with its size and direction. (Guide: Worked example 2; Practice Q4)
- I can find the impulse on each part of a system and the external impulse on the whole system from changes in momentum. (Guide: Worked example 1; Practice Q5(e))
Reasoning and skills
- I can plot total momentum against time from sensor data and find a net external force from the slope. (Guide: “Testing conservation in the lab”; Practice Q5)
- I can describe a lab procedure to test whether momentum is conserved in an interaction. (Guide: “Testing conservation in the lab”)
- I can draw a before-and-after sketch and a momentum vector diagram for a collision. (Guide: Figure 2)
- I can argue qualitatively about three-dimensional cases, such as why an object at rest that splits in two sends the pieces in opposite directions. (Practice Q7)
All ticked? Move on to Topic 4.4, Elastic and Inelastic Collisions, or return to the course roadmap.