A-LevelPhysicsGravitational fields9702/42 · May/June 2017 · Q17 Marks

Define gravitational field strength.

(a)Define gravitational field strength.[1]
(b)(i)Assuming that the comet has constant density, calculate the gravitational field strength on the surface of the comet. field strength = ................................................................ Nkg⁻¹ [2][2]
(b)(ii)A probe having a weight of 960 N on Earth lands on the comet. Using your answer in (i), determine the weight of the probe on the surface of the comet. weight = ........................................................................ N [2][2]
(c)A second comet has a length of approximately 4.5 km and a width of approximately 2.6 km. Its outline is illustrated in Fig. 1.1. Suggest one similarity and one difference between the gravitational fields at the surface of this comet and at the surface of the comet in (b). similarity: ..................................................................................................................................................... difference: .................................................................................................................................................... [2][2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.

[B1] force per unit mass
[C1] g = GM/r²
[A1] = (6.67 ×10⁻¹¹ × 1.0 × 10¹³) / (3.6 × 10³)²
[A1] = 5.1 × 10⁻⁵ N kg⁻¹
[C1] mass = (960/9.81) kg
[A1] weight on comet = (960/9.81) × 5.1 ×10⁻⁵
[A1] = 5.0 x 10⁻³ N
[B1] similarity: e.g. both attractive/pointed towards the comet e.g. same order of magnitude
[B1] difference: e.g. radial/non-radial e.g. same (over surface)/varies (over surface)

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.