Initially, both legs of a mercury manometer are open to the atmosphere, and the mercury height in the left leg is \(40.0 \mathrm{~mm}\). You inflate a balloon until it has a surface area of \(0.300 \mathrm{~m}^{2}\) and affix its open end to the opening of the manometer's right leg. When you do this, the mercury level in the left leg changes to \(65 \mathrm{~mm}\). What is the magnitude of the inward force exerted by the balloon's elasticity on the air in the balloon? The mass density of mercury is \(13.5 \times 10^{3} \mathrm{~kg} / \mathrm{m}^{3}\).