Cambridge International AS and A Level Physics Practical 2: Mechanics and Materials Experiments

Mechanics and materials experiments provide representative contexts for the transferable skills assessed in Cambridge International AS and A Level Physics 9702 Papers 3 and 5. The syllabus does not prescribe a fixed catalogue of practicals. Instead, candidates must set up unfamiliar apparatus, collect a useful range of accurate data, process a graph, draw a bounded conclusion and evaluate the actual method.

Official practical boundary

Paper 3 can present two experiments in different areas of physics without requiring prior theory knowledge. The instructions and supplied information control the task. Candidates must collect an appropriate quantity and range of data, repeat readings where suitable, record measurements consistently, plot and interpret a trend, and evaluate a deliberately imperfect method in Question 2.

Paper 5 can ask for a workable plan in an unfamiliar context. The response must identify variables, explain how quantities are changed and measured, control relevant conditions, show a labelled apparatus arrangement, state how the data produce a conclusion and address realistic safety risks.

The mechanics and materials methods below are reusable patterns, not predictions of named examination experiments.

Time motion over a useful interval

For average speed, measure a clearly defined distance and the corresponding travel time. Mark both endpoints, keep the path geometry fixed and choose a distance long enough that timing resolution is a small fraction of the interval. A vague start or finish point creates uncertainty even when the stopwatch displays many digits.

For acceleration, use successive displacement-time measurements, light gates or a motion sensor as allowed by the apparatus. A light gate can determine an interrupt time; with a card of measured length, speed follows from card length divided by interrupt time. Two gates can compare speeds at known positions. State which measured length belongs in the calculation.

Release an object without an unintended push. A mechanical release, electromagnet or consistent support removal may reduce variation. Align the track so the intended direction of motion is controlled. If friction or air resistance matters, identify its effect on the measured relationship rather than merely writing that friction exists.

Repeat time measurements and use a mean. For periodic motion, time several complete cycles from one defined phase point and divide by the number of cycles. More cycles increase total time, but too many can allow amplitude or conditions to change, so justify the chosen compromise.

Measure forces and moments

Check that a newton meter reads zero before loading and keep the force along its calibrated axis. Avoid reading while the pointer oscillates. If a hanging mass supplies force, use the stated gravitational field strength and include the mass of any hanger when it contributes.