Problem-solving and application
- Syllabus
- 2024
- Topic
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- Level
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Learning objectives
Turn practical measurements into the required result
A practical problem is solved by translating the measurements into the quantity required, then choosing an operation or physics relationship that represents that quantity. The apparatus story provides context; the requested quantity decides which data matter.
Use this sequence: identify the required quantity and unit → label the relevant measurements → write the relationship in words or symbols → convert units if necessary → calculate with meaningful intermediate working → check that the result has the requested unit and is physically possible.
Example: a container has mass 75 g and the container plus liquid has mass 149 g. The liquid alone has mass 149−75=74 g. A listed volume of 88 cm³ is not needed because the target is mass, not density.
Do not automatically use every number. A combined measurement is not the same as the part being asked for, and a numerical answer without the correct unit or a context check may describe the wrong physical quantity.
Connect a practical situation to the physics that explains it
Applying physics in a practical context means using a relevant principle or relationship to explain what the apparatus, variables and observations represent. The context may be unfamiliar, but the physics link should be explicit.
Build the link in four moves: identify the system and what is measured → select the physics idea that connects those quantities → state how a change or observation follows from that idea → use the given evidence to support the result or explanation.
For the liquid data, subtracting the empty container gives the liquid mass, 74 g. If the liquid's density is required, the relevant relationship is density = mass ÷ volume, so the measured mass and 88 cm³ volume now both matter. The same data can therefore serve different purposes depending on the physics quantity requested.
Naming a law, formula or piece of apparatus is not yet an application. The answer must connect the physics to the specific measurement or observation; details that do not affect that connection should not be forced into the reasoning.