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Physics · WORK, ENERGY AND POWER

हिन्दी

Given below are statements regarding the scalar product and work done: (A) The scalar product of two vectors obeys commutative as well as distributive laws. (B) The scalar product of two non-zero vectors is zero only when the vectors are antiparallel. (C) When a body undergoes circular motion under a central force, the instantaneous work done by the central force is identically zero. (D) The work done by friction on an object is strictly always negative, regardless of the frame of reference. Choose the correct answer from the options given below:

  1. (A) and (B) only
  2. (B) and (D) only
  3. (A) and (C) only
  4. (B) and (C) only

Correct answer · Option 3

(A) and (C) only

Explanation

(A) is correct as dot product is commutative and distributive. (B) is false as it is zero when vectors are perpendicular. (C) is correct as central force is perpendicular to displacement. (D) is false as static friction can do positive work in different frames.

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