An O2− ion moves from a region where its electric potential energy is 12.0 × 10−18 J to one where its electrical potential energy is 7.6 × 10−18 J. Use e = 1.602 × 10−19 C. a. What is the change in potential energy?
b. What is the change in electrical potential (i. e. “voltage”)?

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.