Zaymiey

⚛️ Physics  ·  Gravitation  ·  NEET & JEE

A satellite changes orbit from r<sub>1</sub> to r<sub>2</sub> (r<sub>2</sub> > r<sub>1</sub>). Change in KE is:

Answer: Negative (decreases).

  • A Positive (increases)
  • B Negative (decreases)
  • C Zero
  • D Depends on mass

Correct answer: B. Negative (decreases)

Explanation: KE = GMm/(2r). As r increases, KE decreases. Energy must be added to raise orbit but KE actually decreases.

Variation of g with Height and Depthgg_surfaceAbove surface: g ∝ 1/r² (falls off curving down)Below surface: g ∝ r (falls off LINEARLY)Earth's surface (r = R)centre (r=0): g=0g is MAXIMUM exactly at the surface - it decreases in both directions, but by different laws

g is maximum at Earth's surface; going up, it falls off as 1/r² (inverse-square); going down, it falls off linearly with depth (since only the mass enclosed within radius r contributes), reaching zero at the centre.

Concept context

Universal gravitation, orbital mechanics, gravitational potential, and escape velocity.

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