A spherical balloon that has a diameter of \(0.500 \mathrm{~m}\) and contains \(1.00 \mathrm{~mol}\) of helium gas is left in the Sun for \(10.0 \mathrm{~min}\). During that interval, the Sun irradiates the balloon with an average intensity of \(1120 \mathrm{~W} / \mathrm{m}^{2}\), all of which is absorbed. Before being warmed by the Sun, the average speed of the helium atoms is \(367 \mathrm{~m} / \mathrm{s}\). What is their average speed after being warmed? Assume the balloon diameter remains constant. The mass of a helium atom is \(6.646 \times 10^{-27} \mathrm{~kg}\).