Suppose that 4 J of work is needed to stretch a spring from its natural length of 26 cm to a length of 41 cm a How much work in J is needed to stretch the spring from 28 cm to 33 cm Round your answer to two decimal places 0 80 J 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 67 07 X cm