What Molecules in Air Hit Dust Particles?

[Mozart]

On a chemistry test I just had one of the questions was. Which part of air hits dust particles? I just didn't know what to write. Some of my friends said that nothing hits it, and that it moves simply because it has kinetic energy and then other people said it was N2 that hits it. Does anyone know what the real answer is?

 

[Gokul43201]

We'd like to know what the real question is.

Which part of air hits dust particles?

If this is all there is to the question, it's not worth wasting your time trying to answer it. The question, as quoted, is too vague and ill-defined to appear on a science test. Whoever made the test did a terrible job.