Answer: Passenger BalloonsLong-distance balloon flights

Chapter , Problem 17P

(choose chapter or problem)

Problem 17P

Passenger Balloons

Long-distance balloon flights are usually made using a hot-air balloon/ helium-balloon hybrid. The balloon has a sealed, flexible chamber of helium gas that expands or contracts to keep the helium pressure approximately equal to the air pressure outside. The helium chamber sits on top of an open (that is, air can enter or leave), constant-volume chamber of propane-heated air. Assume that the hot air and the helium are kept at a constant temperature by burning propane.

A balloon is at a height of 5.0 km and is descending at a constant rate. The buoyancy force is directed __________________; the drag force is directed __________________.

A. Up, up

B. Up, down

C. Down, up

D. Down, down