A hot-air balloon is drifting in level flight due east at 2.9 m/s due to a light wind. The pilot suddenly notices that the balloon must gain 20 m of altitude in order to clear the top of a hill 100 m to the east. (a) How much time does the pilot have to make the altitude change without crashing into the hill?
(b) What minimum constant upward acceleration is needed in order to clear the hill?
(c) What are the horizontal and vertical components of the balloon's velocity at the instant that it clears the top of the hill?