10. DETAILS SCALCET8 6.4.015. A cable that weighs 4 Ib/ft is used to lift 850 lb of coal up a mine shaft 350 ft deep. Find the work done. Show how to approximate the required work by a Riemann sum. (Let x be the distance in feet below the top of the shaft. Enter x - as x.) lim Ax 1-+ 00 i= 1 Express the work as an integral. dx Evaluate the integral. ft - lb