SACE Year 11 Physics practice exams with worked answers

An investigation begins by turning a broad concern into a question that measurements can answer. “What affects a spring?” is too broad because force, material, coil diameter and temperature could all matter. Deconstruct it by identifying the system, the possible causes, the measurable response and practical restrictions. A testable question specifies a relationship and conditions: how does applied force affect the extension of this spring within its elastic range? A hypothesis predicts a pattern and supplies a physical reason.

Predicting proportional extension is useful because the prediction can be compared with a graph; claiming that springs are interesting cannot be tested.

The independent variable is deliberately changed; the dependent variable is measured. Controlled factors are held approximately constant to avoid competing explanations. For a spring, change applied force, measure extension, and retain the same spring, ruler position and temperature. Distinguish a controlled factor from an uncontrollable one. Room vibration may remain despite precautions; acknowledge it and reduce its influence by waiting for oscillations to settle. Specify equipment with suitable range and resolution.

Resolution is the smallest displayed increment, not a guarantee that the displayed value is accurate.

A reproducible procedure gives another investigator enough detail to repeat the method. State how zero readings are obtained, how variables are changed, when observations are made and how repeats are recorded. Choose several evenly spread settings and repeat each setting, rather than taking many readings at only one setting. A pilot trial helps identify the safe range and whether the response is measurable. Repeating measurements estimates scatter; increasing the range helps distinguish competing relationships. Neither strategy automatically removes bias.

Ethical practice includes truthful records, credit for shared data, consent before recording classmates, and respectful sharing of roles. Safety measures must address a specific hazard rather than simply saying “be careful”.