A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of 60 kg, how long did it take him to reach that speed? a. 0.33 s
b.0.83 s
c. 1.2 s
d. 3.0 s

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.