Basic Thermodynamics ~ J. Pohl © www.THERMOspokenhere.com () -  ()

Hot Air Balloon

A hot-air balloon flies due EAST, at an steady speed of 15 mph and at a constant elevation of 100. We are at an intersection. The balloon will pass directly above us.

a) From the instant the balloon is directly above, obtain an equation for its distance "from us" as a function of time.

b) In the epoch of this event, at what time is the balloon 1280 feet from us?








A balloon of diameter 60 ft is initially on the ground, 6000 feet away. Once released, the balloon, floats upward 6 feet per second in a steady wind at 3 miles per a hour on a path directly toward us.

a) How high will the balloon be when it passes directly above?

b) When is the balloon closest to us?

c) When the balloon is closed, how far away is it?

#62 (3): At the seashore, the surf is flat. The breeze is steady at 1/2 mph breeze blowing directly out to sea. Suppose a child playing with a light beach ball drops it and the breeze takes it offshore. Two minutes later you sit at the water’s edge 200 feet away, see the child’s ball and decide to retrieve it. Suppose you can swim at 2 feet per second and run at 10 feet per second.

a) What is the very least time required for you to retrieve the ball?

b) If you swim directly from where you are what will be the least time?