A 0.00290 kg air-inflated balloon is given an excess negative charge q = -3.00 x 10-8 C by rubbing it with a blanket. It is found that a charged rod can be held above the balloon at a distance of d = 0.0660 m to make the balloon float. How much charge 92 does the rod have? Model the balloon and rod as point charges. The Coulomb force constant is 1/(4x60) = 8.99 x 10 N-m/C", and the acceleration due to gravity is g = 9.81 m/s. 2 2