You and Tim float a long string of closely spaced helium- filled balloons over his used-car lot. You secure the two ends of the long string of balloons to different points on the ground so that the balloons float over the lot in an arc. What is the name of this arc? (Why could this exercise have been included in Chapter 12?)
Gas balloons will rise in air when the balloons dense is less than air.the balloons which are filled with gas less dense than ordinary air , which keeps the balloons from collapsing while keeping it light. The atmosphere has no definite shape and there is no top furthermore,unlike, the water ,the atmosphere becomes less dense with altitude,a released helium filled balloons does not rise in atmospheric surface,A balloon will rise only so long as it displaces a weight of air greater than its own weight of displaced air equals to the total weight of the balloons, upward acceleration of the balloon ceases or when the buoyant force on the equals to weight ,the balloon will cease to rise and when the average density of the balloon equals the density of the surrounding air, the balloon will cease rising. Helium filled balloons usually break when released in the air because as the balloon rises to regions of less pressure, the helium in the balloon expands, increasing the volume.