7.6 Webassign Answers

Step by step solutions: 2 3 4 5

- A variable force of 7x^-2 pounds moves an object along a straight line when it is x feet from the origin. Calculate the work done in moving the object from x=1 ft to x=18 ft. (Round your answer to two decimal places.)
- A force of 14lb is required to hold a spring stretched 2 in. beyond its natural length. How much work W is done in stretching it from its natural length to 8 in. beyond its natural length?
- A spring has a natural length of 22cm. If a 22-N force is required to keep it stretched to a length of 40 cm, how much work W is required to stretch it from 22 cm to 31 cm? (Round your answer to two decimal places.)

4. Suppose that 6J of work is needed to stretch a spring from its natural length of 24 cm to a length of 45 cm. - If 24 J of work are needed to stretch a spring from 13 cm to 17 cm and 40 J are needed to stretch it from 17 cm to 21 cm, what is the natural length of the spring?