Question

4. In 1897, a Ferris wheel with a diameter of 86.5 m was built in London. The wheel held 10 first-class and 30 second-class cabins, and each cabin was capable of carrying 30 people. Consider two cabins positioned exactly opposite each other. Suppose one cabin has an unbalanced charge of 4.8 nC and the other cabin has a charge of 16 nC. At what distance from the 4.8 nC charge along the diameter of the wheel would the strength of the resultant electric field be zero?

Answer 1

We know that F = k q/q^3/r^2 Let distance from 4.8 nc charge be x distance from 16 nc is 86.5 - x when net force gets equal to 0 then the force of each on that point is equal. Hence net force on any charge at that point will be �0�. So let charge at that point be 1c for convenience k 4.8 E - 9(1)/x^2 = k 16 E - 9(1)/(86.5 - x)^2 rightarrow 16E - 9x^2 = 4.8 E - 9 (7482.25 - 173 x + x^2) rightarrow 3.59 E - 5 - 8.30 E - 7x + 4.8 E = 9x^2 rightarrow 1.12 E - 8x^2 + 8.30 E - 7x - 3.59 E - 5 = 0 [Therefore x = 30.4 m from the 4.8 nc charge]