Question

what makes some collisions elastic and others inelastic? if there is energy lost in the collision to sound, heat, etc., the collision is elastic. if the collision involves bouncing, it is elastic. if the collision involves sticking together, it is elastic. if there is no loss of kinetic energy in the collision, it is elastic.

Explanation:

To determine the correct answer, we analyze the definitions of elastic and inelastic collisions:

• An elastic collision is defined as a collision where kinetic energy is conserved (no loss of kinetic energy).
• An inelastic collision involves a loss of kinetic energy (often to sound, heat, deformation, etc.).
• Let's evaluate each option:
• Option 1: If energy is lost (to sound, heat, etc.), the collision is inelastic, not elastic. Eliminate.
• Option 2: Bouncing alone does not guarantee elasticity. Some bouncing collisions can still lose kinetic energy (e.g., a ball bouncing with less height each time due to air resistance and deformation). Eliminate.
• Option 3: Sticking together (perfectly inelastic collision) involves a significant loss of kinetic energy. Eliminate.
• Option 4: This matches the definition of an elastic collision (no loss of kinetic energy).

Answer:

D. If there is no loss of kinetic energy in the collision, it is elastic.