2025 · Paper 2 · Physics
Question 12
The printed question, the official key, and each model’s JSON answer plus the reasoning it wrote.
Q12
Official 2.3 – 2.4

Model answers
Claude Fable 5.1
Anthropic
2.331
Claude Fable 5.1 reasoning
Geostationary satellite: period T₁ = 24 h at radius r₁. By Kepler's third law, T ∝ r^(3/2): T₂/T₁ = (r₂/r₁)^(3/2) = (1/1.21)^(3/2) = (1/1.1)³ = 1/1.331 So T₂ = 24/1.331 hours, i.e. ω₂ = 1.331 ω₁ in magnitude. The second satellite orbits in the opposite sense, so the relative angular velocity as seen from the geostationary satellite is: ω_rel = ω₁ + ω₂ = ω₁(1 + 1.331) = 2.331 ω₁ Relative period: T_rel = 2π/ω_rel = T₁/2.331 = 24/2.331 hours Hence p = 2.331.
GPT 6 Astra
OpenAI
2.331
GPT 6 Astra reasoning
No written reasoning was returned for this item.
GPT 5.6 Luna
OpenAI
2.331
GPT 5.6 Luna reasoning
No written reasoning was returned for this item.