Answer to Question #65018 in Physics for Helen

Question

Heinz Doofenshmirtz uses his Static Electro-Amplif-inator to put a charge on Balloony1
and an identical ordinary balloon (the same charge is applied to each balloon). The two
balloons then repel one another so that when Doofenshmirtz holds them by their strings
(the length of string for each balloon is 85.0 cm) the total angle between the balloons is
28.0◦
. The helium in each balloon provides a net buoyant force of 1.35×10−1 N directly
upward (to be clear, the difference between the buoyant force up and the gravitational
force down is 1.35 × 10−1 N for each balloon). What is the charge on each balloon?