Question

Choose the correct option who describes a perfectly inelastic collision free of external forces?

• A. Total linear momentum is never conserved.
• B. Total linear momentum is sometimes (but not always) conserved
• C. Kinetic energy is never conserved
• D. Kinetic energy is sometimes (but not always) conserved
• E. Kinetic energy is always conserved

Answer 1

Answer: (C)

Kinetic energy is never conserved

As the total external force on the system is zero during collision, thus total linear momentum is always conserved (in perfectly inelastic collision also).

Also in case of perfectly inelastic collision, the colliding objects stick together and some kinetic energy is lost either in the form of heat or deformation. Thus kinetic energy is never conserved during perfectly inelastic collision.