Suppose that 6 J of work is needed to stretch a spring from its natural length of 32 cm to a length of 44 cm. (a) How much work is needed to stretch the spring from 36 cm to 40 cm? (Round your answer to two decimal places.) (b) How far beyond its natural length will a force of 40 N keep the spring stretched? (Round your answer one decimal place.) 4 8 cm 11. [-/4 Points] DETAILS SCALCET8 6.4.015. MY NOTES ASK YOUR TEACHER A cable that weighs 4 lb/ft is used to lift $50 lb of coal up a mine shaft 300 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 4X Express the work as an integral. Evaluate the integral. ft - lb