The gravitational field near Earth's surface is approximately uniform because
A{'text': 'Earth is treated as a flat plane over small regions', 'label': 'A'}
B{'text': "Distance changes are negligible compared to Earth's radius", 'label': 'B'}
C{'text': "The Sun's gravity overrides Earth's effect completely", 'label': 'C'}
D{'text': "Earth's gravity acts repulsively at small heights above", 'label': 'D'}
Answer & Solution
Correct answer: B. {'text': "Distance changes are negligible compared to Earth's radius", 'label': 'B'}
1. Earth's radius is about 6400 km.
2. Vertical displacements of a few metres are negligible compared to R.
3. So (R + h) ≈ R and g is essentially constant over such heights.
4. This is why kinematics problems near the ground use a constant g = 9.8 m/s².
_Source: NCERT Class 11 Physics, Ch 7 "Gravitation", §7.4_
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