Earth density ~ 1g/cm^3 = 1000kg/m^3 ~ Asteriod density Asteroid Radius = 1km. Asteroid mass = 4/3piR^3density = 4.2x10^12kg acceleration = G M/R^2 = 280 micro

Earth density ~ 1g/cm^3 = 1000kg/m^3 ~ Asteriod density Asteroid Radius = 1km. Asteroid mass = 4/3piR^3density = 4.2x10^12kg acceleration = G M/R^2 = 280 micrometers/second if initial velocity is zero, a dust particle will settle in about 300 seconds from a height of 10m at this acceleration. They can always escape if initial speed is high, but if not, they will settle down pretty fast. Use science!