When a fast moving particle runs into a slower moving particle
what happens ?

It depends upon the mass of the particles also. Assuming equal mass, then the slower moving particle gains some energy, and the faster-moving particle loses energy. However, if the slower moving particle had greater mass, it could transfer energy to the faster-moving particle.

Explanation:

Hope I could help! :)

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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