in the particle under constant acceleration model we identify the variables and parameters Vxi, Vxf, ax, t, and xf-xi. Of the equations in the model, Equations 2.13-2.17, the first does not involve xf-x, the second and third do not contain ax, the fourth omits Vxf, and the last leaves out t. So, to complete the set, there should be an equation not involving Vxi. Derive it from the others.

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.