Cambridge International AS & A Level · P3 · structured
Draw an instantaneous-rate construction
AS practical 7: a tangent describes one instant · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 6
- Topics
- 3
- Answer
- Complete
Draw a smooth fitted curve for the constructed trolley data. Draw a tangent at t=1.5 s, mark a large triangle on the tangent and calculate the instantaneous velocity. Explain why the tangent intercept is not necessarily the initial displacement. Constructed illustrative data (not observed experimental evidence). Columns: t / s (constructed) | s / m (constructed). Rows: 0.0 | 0.00; 0.5 | 0.04; 1.0 | 0.16; 1.5 | 0.34; 2.0 | 0.61; 2.5 | 0.93; 3.0 | 1.36.
- (a)
Draw the curve and tangent.
3 marks - (b)
Use a large tangent triangle for velocity.
2 marks - (c)
Interpret the tangent intercept.
1 mark
Ready to self-mark?Reveal the detailed answer guide
(a)
Draw the curve and tangent.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
Smooth fitted curve and correct local tangent at 1.5 s.
(b)
Use a large tangent triangle for velocity.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
About 0.45 m s^-1, supported by the drawing.
(c)
Interpret the tangent intercept.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
It is not necessarily initial displacement because the tangent is only a local linear approximation.
Complete marking guidance
Use these worked steps alongside the part-by-part answers. They explain the method and mark allocation; they do not add extra marks.
- Smooth fit with no point-to -point corners: one mark.
- Tangent at the specified instant with plausible local direction: two marks.
- Large triangle on the tangent, not a secant through data: one mark.
- Correct gradient with m s^-1 consistent with the drawing: one mark.
- Local tangent is not the original full-time motion law: one mark.
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