If a room has dimensions 3m x 4m x 5m, what is the mass of air in the room if density of air at NTP is 1.3kg/m^(3)

If a room has dimensions 3m x 4m x 5m, what is the mass of air in the

1.	If a room has dimensions 3m x 4m x 5m, what is the mass of air in the room if density of air at NTP is 1.3kg/m^(3)
Answer» Solution :`m=rhoxxv=(1.3kg//m^(3))(3xx4xx5m^(3))=78 kg` i.e. ,mass of AIR in the ROOM is 78 kg which is unbelievable (as air is assumed to be WEIGHTLESS) but is TRUE.