OnlineCBT
Physics · WORK, ENERGY AND POWER
हिन्दीConsider the following statements regarding the work-energy theorem and mechanical principles: (A) The work done by a force depends on the choice of the reference frame. (B) For an isolated two-body system, the sum of internal mutual forces is always zero, so the sum of work done by mutual forces \( W_{12} + W_{21} \) must always be zero. (C) The work-energy theorem is valid in non-inertial reference frames provided pseudo forces are included. (D) In an elastic collision, total kinetic energy is conserved at each and every instant during the impact. Choose the correct answer from the options given below:
Correct answer · Option 1
(A) and (C) only
Explanation
Statements (A) and (C) are correct. (B) is false because displacements of interacting bodies need not be identical, so \( W_{12} + W_{21} \neq 0 \) in general. (D) is false because during collision deformation occurs and part of KE is momentarily stored as elastic potential energy.
