A50.0-kg box is resting on a horizontal floor. a force of 250 n directed at an angle of 32.0° below the horizontal is applied to the box. what is the minimum coefficient of static friction between the box and the surface required for the box to remain stationary?

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.