A block on a slope. Time it between two light gates.
A trolley or block on an inclined plane is a regular Question 1 family in Paper 5. Here a wooden block is released from rest at light gate A and you measure the time t it takes to reach light gate B, a distance d down the plane, as the angle θ of the plane changes. Watch the set-up built step by step, with the variables and the graph beside it, then build it yourself and check it against the mark points.
Past-paper referenceOriginal experiment, wording and figures, written in the style of Cambridge AS & A Level Physics 9702 Paper 5, Question 1. It is not copied from a past paper. The “what the examiners said” notes are our paraphrase of the Principal Examiner Reports for Teachers.
Practise next: 9702/51 May/June 2023, Question 1 (a cube on a plane pulled by a falling cylinder over a pulley) · official past papers
Practise next: 9702/51 May/June 2017, Question 1 (speed of a block on an inclined plane as the angle changes) · official past papers
Practise next: 9702/52 May/June 2016, Question 1 (acceleration of a trolley pulled up an incline) · official past papers
Examiner reports used: 9702 June 2016, March 2017, June 2017 and June 2023.
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What a full-mark diagram shows
A workable, supported plane
The plane held by a stand and clamp on the bench, so it is stable and its angle can be changed. Labels on the plane, the support and the instruments.
Measuring the angle θ
A protractor at the bottom of the plane, or a rule to measure marked lengths with sin θ = h / L.
Measuring t
Two light gates a distance d apart, connected to an electronic timer (or data logger). The card on the block starts and stops the timer.
Measuring d, and keeping it
A rule placed to measure d between the beams, with both gates clamped to the plane so d stays the same as θ changes.
Habits the examiner reports keep asking for
Write “keep d constant”, not “control d”, and say how: the gates move with the plane.
Light gates need a timer. Say what starts and stops it, and draw the gates where they are.
Show a release from rest, for example a set square that holds the block and is then moved away.
Additional detail must be a method: a large d to make t longer, or “for the same angle, measure t again and average”.
Safety belongs to this experiment. A sand tray or cushion to catch the block, with the reason.