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NEETPhysicsGravitation

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): If a body is projected from the earth's surface with a speed of 3v_e (where v_e is the escape velocity), its speed at interstellar distance (infinity) is 2 2 v_e . Reason (R): For a body projected with a speed v > v_e , its speed at infinity is not given by the linear difference (v - v_e) . In the

Options

  1. ABoth Assertion and Reason are true and Reason is the correct explanation of Assertion.
  2. BBoth Assertion and Reason are true but Reason is not the correct explanation of Assertion.
  3. CAssertion is true but Reason is false.
  4. DAssertion is false but Reason is true.

Correct answer

B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

Step-by-step solution

Assertion (A) is true: By the conservation of mechanical energy, the velocity of a body at infinity ( v_ ) when projected with a velocity v is given by v_ = v^2 - v_e^2 . Substituting v = 3v_e : v_ = (3v_e)^2 - v_e^2 = 9v_e^2 - v_e^2 = 8v_e^2 = 2 2 v_e . Reason (R) is true: The speed at infinity is indeed not calculated by the linear subtraction v - v_e . A common misconception is to write v_ = 3v_e - v_e = 2v_e , which is incorrect. However, Reason (R) is merely a negative statement pointing out that the linear fo

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