The diagram shows a heating curve for a substance. a graph titled heating curve of substance it shows heat added in joules on the x-axis, and temperature in degrees celsius on the y-axis on a scale of 0 to 100. the graph has a diagonal line from negative 5 degrees up to zero degrees labeled u. a horizontal line segment at zero degrees labeled v. a diagonal line segment from zero degrees up to 120 degrees labeled w. a horizontal line segment at 120 degrees labeled x and then another diagonal segment labeled y. which segment shows the substance changing from a gas to a liquid? x-y y-x w-x x-w

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.