This is due to inertia of rest .1st law of Newton's states the law of inertia in which a body remains in the state of rest until and unless supplied with any other unbalanced force .inertia of rest acts as particles want to be in state of rest and when beaten they acquire intertia of motion.due to dust having inertia does not move and resists motion but force pushes the dist particles.. hopefully helped!! Have a GD day!