Question

Question #26ed8

Answer 1

It decreases since there are less particles present per unit volume.

Explanation:

Since density is defined as the mass per unit volume, `rho=m/V`, it implies that as one rises up, the air particles become less frequent in the same unit of volume and hence the density of the air is less at higher altitudes due to the lower mass per unit volume of air particles.
Also, the pressure is less at higher altitudes since the air particles experience less collisions per unit time.