Question

the distance that a spring varies directly as the force applied to the spring. A force of 70 pounds is needed to stretch a spring 7 inches. what force is required to stretch the spring 13 inches?

Answer 1

Since the distance that the spring stretchs varies directly as the force applied to the spring, we can use a rule of three to find the force required to stretch the spring 13 inches:

`\begin{gathered} 70\text{ pounds}\to7\text{ inches} \\ x\text{ pounds}\to13\text{ inches} \\ \\ (70)/(x)=(7)/(13) \\ (10)/(x)=(1)/(13) \\ x=10\cdot13 \\ x=130 \end{gathered}`

So the force required is 130 pounds.