Multiple choice

Directions: There are two statements, one labeled the Assertion (A) and the other labeled the Reason (R). Examine the statements and decide if the Assertion A and Reason R are individually true and if so, whether the reason is the correct explanation of the assertion. Select your answers to the question from the codes given below:

Assertion (A): The gravitational force acting on a planet revolving around the sun does not work on the planet. Reason (R): The force is always at right angles to the direction in which the body is moving.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true and R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gravitational force acting on a planet in circular motion is directed towards the center of the sun, while the instantaneous displacement vector is tangential to the orbit. Since work done is given by the dot product of force and displacement, and the angle between them is 90 degrees, the work done is zero.

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