Cambridge International AS & A Level · 13 · structured
Define and draw a gravitational field
Gravitational fields: force per mass and field-line maps · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 6
- Topics
- 2
- Answer
- Complete
Define gravitational field strength. Sketch the field outside an isolated spherical planet and the field in a small region immediately above its surface. Explain the arrow directions and spacing.
- (a)
Define gravitational field strength, including its unit.
2 marks - (b)
Sketch and explain the spherical and local near-surface field maps.
4 marks
Ready to self-mark?Reveal the detailed answer guide
(a)
Define gravitational field strength, including its unit.
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
Gravitational force per unit small test mass; N kg⁻¹.
(b)
Sketch and explain the spherical and local near-surface field maps.
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
Radial inward noncrossing lines; weaker farther out; local equally spaced parallel downward arrows, valid only over a small region.
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.
- State g = F_grav/m and N kg⁻¹, with direction equal to the force direction.
- Draw radial noncrossing exterior field lines with arrowheads towards the planet.
- Explain that their increasing separation represents decreasing strength.
- Draw a local patch with straight parallel equally spaced downward arrows and identify the uniform-field approximation.
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