Question

Why does kinetic energy of molecules of a substance increase when its temperature is raised ?

Answer 1

Because an increase in heat is just an increase in the vibrational energy of the atoms, or molecules of a substance. So if you increase the temperature and hence the heat, there is more movement (vibration) in the atoms which translates to more kinetic energy

Answer 2

Answer:

This is because when substance is heated it's molecules starts moving at very high speed so lunatic energy increases