Air only has a density of 1.3kg/m². What is the mass of
3m^3 of air?

m = 3.9 [m³]

Explanation:

We must remember that the density of the substance is defined as the relationship between mass over volume. That is expressed in the following equation:

where:

Ro = density = 1.3 [kg/m³]

m = mass [kg]

V = volume = 3 [m³]

Now replacing the values.

what type of charge does it have? negative

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s