A needle 5cm long can just rest on the surface of the water without wetting. What us it's weight? Surface tension is 0.007N/m

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

Write down two additional questions about earth's magnetic field that will make your presentation more informative.

What’s #16 asking me and how do i solve it?