hey a question from the new CIE Physics Book - Exam - style question(they dont have answers)
1.A hot air balloon its basket and passengers have a total mass of 450kg. The inflated balloon holds 3000m^3 of air.
(a) minimum forced needed to lift balloon of the ground? - 4500 N
(b) Atm pressure is 1.03 x 10^5 abd density of air is 1.23kg/m^3
(i) calculate mass of 3000m^3 air? - 3690kg
(ii) Calculate Number of Moles in the balloon, Consider air relative Mr as 29 ? 1.27 x 10^5 mol
THIS IS PRIOR INFORMATION AND CALCULATIONS DONE BY ME..the next two parts i dont
know
c. As the air is heated some of it is expelled through a vent at the top of the balloon. Calculate max mass of air that can remain in balloon to give sufficient upthrust for the balloon to just the leave the ground?
DONT KNOW
d. Calculate the minimum temperature of the air inside the balloon for the balloon to just lift off the ground??? DONT KNOW