You lift your pet cat vertically by 2m and then you lower it vertically by 2m .during this exercise is the total work done by gravity positive negetive or zero?

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)