Question

In inelastic collision

• A. momentum, kinetic energy and total energy are conserved
• B. momentum, kinetic energy and total energy are not conserved
• C. momentum, and kinetic energy are conserved but total energy is not conserved
• D. total energy and momentum are conserved but kinetic energy is not conserved

Answer 1

Answer: (D)

total energy and momentum are conserved but kinetic energy is not conserved

Answer 2

In a collision, the effect of external forces such as gravity or friction are not taken into account as due to small duration of collision (At) average impulsive force responsible for collision is much larger than external force acting on the system and since this impulsive force is 'internal' therefore the total momentum of system always remains conserved. In a collision total energy is also conserved. In an inelastic collision kinetic energy appears in other forms. In some cases
$(KE)_{f} < (KE)_{i}$
such as when initial KE is converted into internal energy of the product while in other cases
$(KE)_{f} > (KE)_{i}$
such as when internal energy stored in the colliding particles is released.