QUESTION 7 [3 pts] A balloon is filled with helium gas at sea level where the temperature was 27 9C. The pressure inside the balloon is 1.15 bar and the volume of the gas is 74.5 L. The balloon ascends to an altitude where the temperature drop causes the balloon's volume to decrease to 68.7 L. The pressure inside the balloon remained at 1.15 bar throughout the ascent. How much M (in joules) was done on the gas due to the volume contraction? l ,'5 79:1? . 74 .s K 1,.\" VP _ (p f. \"l L x -'-~ ' nnnn L