Answer:
Average kinetic energy decreases
Thermal energy decreases
Temperature decreases
Step-by-step explanation:
As the particles in a substance slow down then the kinetic energy of all the molecules will decreases.
As we know that kinetic energy is given as

As we know that sum of kinetic energy of all the molecules is the molecules is known as internal thermal energy.
So here since kinetic energy decreases so internal thermal energy also decreases.
Now as we know that total internal thermal energy directly depends on temperature as

so here as internal thermal energy decreases so its temperature also decreases.