Question
For an object in gravitational field, the gravitational potential is the same at two points A and B, but the gravitational field is not the same at these two points. Which one of the following statements is correct?
NDA
General Ability
General Science
2026
NDA 2026 (Phase 1)
NDA General Ability Question (2026) — Solution
Options
- A. Positive work is done by gravity in moving the object from point A to point B.
- B. Negative work is done by gravity in moving the object from point A to point B.
- C. Gravity must be non-conservative in such a region.
- D. No work is done by gravity in moving the object from point A to point B.
Answer
D. No work is done by gravity in moving the object from point A to point B.
Step-by-step solution
The work done by the gravitational force on an object of mass m in moving it from point A to point B is given by W = - U = -m(V_B - V_A) = m(V_A - V_B), where V_A and V_B are the gravitational potentials at points A and B respectively. It is given that the gravitational potential is the same at points A and B, which means V_A = V_B. Substituting this into the work equation, we get W = m(V_A - V_A) = 0. The difference in the gravitational field at the two points does not affect the total work done between these equipotential points, as gravity is a conservative force and work done is independent of the path taken. Therefore, no work is done by gravity in moving the object from point A to point B.
Related: General Ability — General Science · All PYQ Banks