On a perfect fall day, you are hovering at low altitude in a hot-air balloon, accelerated neither upward nor downward. The total weight of the balloon, including its load and the hot air in it, is 20,000 N. (a) What is the weight ofthe displaced air? (b) What is the vol- ume ofthe displaced air?

Explanation:

Since is at test, the buoyancy force, Fb is equal to the weight of the air, W.

W = 20000 N

B.

Density of air = 1.2 kg/m3

Force = mass × Acceleration

= density × volume × acceleration

20000 = 1.2 × Vol × 9.8

Vol = 1700.7 m3.

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