External Assessment Paper 1: Short Responses and Data Interpretation
Paper 1 rewards precise physics vocabulary and clean reasoning rather than long prose. You must be fluent in the syllabus concepts: linear motion and forces, momentum and impulse, circular motion, work, energy and power, gravitational, electric and magnetic fields, DC circuits, and the wave and quantum models of light. Each question usually targets one concept, so identify the principle first, then apply it.
Traps to watch
- Signs and directions: choose a positive direction and state it; a negative acceleration does not always mean slowing down.
- Units: convert grams to kilograms, centimetres to metres, and milliamps to amps before substituting.
- Vector versus scalar: momentum, force and field strength need direction; energy and power do not.
- Rounding: keep extra digits through the working and round only at the end, to the precision of the data given.
- Graph reading: gradient and area are the most common data-extraction tasks, so know which pairs give which quantity.
Worked example
A 0.50 kg ball travelling at 8.0 m/s rebounds at 5.0 m/s. Find the impulse. Take the initial direction as positive. Initial momentum = 0.50 x 8.0 = +4.0 kg m/s. Final momentum = 0.50 x (-5.0) = -2.5 kg m/s. Impulse = change in momentum = -2.5 - 4.0 = -6.5 N s, i.e. 6.5 N s opposite the initial motion. The trap is forgetting the sign reversal.
Rule of thumb
For any graph, ask: what is the gradient, and what is the area under it? On a velocity-time graph, gradient is acceleration and area is displacement. On a force-time graph, area is impulse. On a force-displacement graph, area is work. This single habit answers a large share of Paper 1 data questions.