Suppose that 43 of work is needed to stretch a spring from its natural length of 36 cm to a length of 53 cm. (a) How much work is needed to stretch the spring from 40 cm to 48 cm? (Round your answer to two decimal places.) 3 (b) How far beyond its natural length will a force of 35 N keep the spring stretched? (Round your answer one decimal place.) x cm [0/1 Points]