__.. ..__ -_..___._ -. ..-__._.. _.- -s-...._-._..- -___ According to Hooke's Law, the force required to hold the spring stretched x m beyond its natural length is given by f(x) = kx, where k is the spring constant. Suppose that S J of work is needed to stretch a spring from its natural length of 34 cm to a length of 46 cm. Find the exact value of k, in N/m. NE (a) How much work (in J) is needed to stretch the spring from 36 cm to 38 cm? (Round your answer to two decimal places.) :11 (b) How far beyond its natural length (in cm) will a force of 30 N keep the spring stretched? (Round your answer one decimal place.) E