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JAMB Physics 2014 Question 8

Question 8

Gravitational Field

Calculate the escape velocity of a satellite launched from the earth's surface if the radius of the earth is 6.4 × 106m. [g=10 ms−2]

  1. A.4.2 kms−1.
  2. B.4.0 kms−1.
  3. C.11.3 kms−1.
  4. D.25.3 kms−1.
Show the answer and explanation

Answer: C (11.3 kms−1.)

Explanation

v = √(2gR) = √(2 × 10 × 6.4 × 106) ≈ 1.13 × 104 m s−1 = 11.3 km s−1.