A spring has a natural length of 18 cm. If a 22-N force is required to keep it stretched to a length of 24 cm, how much work W is required to stretch it from 18 cm to 21 cm? (Round your answer to two decimal places.)

Answer 1

Take a look here. The first problem is just like this.

http://tutorial.math.lamar.edu/Classes/CalcI/Work.aspx