Question

6. A hot-air balloon has a volume of 2200 m². The basket, passengers and the balloon fabric (the envelope) weight 5,800 N,excluding the weight of heated gas in the envelope. If the balloon is floating in the air without accelerating upward or downward when the outside air density is 1.23 kg/m³, what is the average density of the heated gases in the envelope?

Fig: 1