Question

The kinetic energy of molecules ____________ when a solid melts.

• A. Increases
• B. decreases

Answer 1

Word Kinetic simply means “produced by movement”. So the kinetic energy of any object is the energy that it has because of its movement.
For example, The moon revolving around the earth, stone falling from the top, and molecules moving in space all have kinetic energy.

When a solid melts it requires energy in the form of heat, as temperature increases the movement of molecules becomes faster, and hence Kinetic energy also increases.

So, The kinetic energy of molecules Increases when a solid melts.