UPSC Prelims 2002·GS1·science-and-technology·space

Assertion (A): Artificial satellites are always launched from the earth in the eastward direction. Reason (R): The earth rotates from west to east and so the satellite attains the escape velocity.

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  1. ABoth A and R are individually true and R is the correct explanation of A
  2. BBoth A and R are individually true but R is not a correct explanation of A
  3. CA is true but R is falseCorrect
  4. DA is false but R is true

Explanation

Assertion A is true because launching a satellite in the eastward direction allows it to take advantage of the earths rotational speed, which provides an initial boost and saves fuel. Reason R is false because the boost provided by the earths rotation is very small compared to the required escape velocity. Escape velocity is the speed needed to break free from the earths gravitational pull entirely, whereas most satellites are launched into specific orbits around the earth. Furthermore, the rotation alone does not make a satellite attain escape velocity; that requires massive thrust from the rocket engines. Therefore, while the earth does rotate from west to east, it is not the reason the satellite attains escape velocity.
science-and-technology: Assertion (A): Artificial satellites are always launched from the earth in the eastward direction. Reason (R): The earth

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