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AP EAMCET202125 Aug 2021Evening ShiftPhysicsCenter of Mass, Momentum and CollisionActual

Assertion (A) In an elastic collision of two billiard balls, the total KE is conserved during the short time of collision of the balls (i.e., when they are in contact). Reason (R) Energy spent against friction does not follow the law of conservation of energy. Codes

Options

  1. ABoth A and R are true and R is a correct explanation for A.
  2. BBoth A and R are true but R is not a correct explanation for A.
  3. CA is true but R is false.
  4. DBoth A and R is false.

Correct answer

D. Both A and R is false.

Step-by-step solution

In an elastic collision of two billiard balls, there is deformation in shape of balls momentarily. During the collision potential energy increases due to deformation of balls and kinetic energy decreases. Hence, total energy remains constant but kinetic energy is not conserved. Law of conservation of energy always applies, in every case. Thus, both Assertion and Reason are false.

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