Question

The elongation E of a spring balance varies directly with the applied weight W. If E=2 when W=18, findE when W=13

Answer 1

E varies directly with W:

`E=k*W`

Use the given data to find the value of the constant k:

`\begin{gathered} 2=k*18 \\ k=(2)/(18) \\ \\ k=(1)/(9) \end{gathered}`

Equation of the relationship:

`E=(1)/(9)W`

Use the equation above to find E when W=13:

`\begin{gathered} E=(1)/(9)(13) \\ \\ E=(13)/(9) \end{gathered}`

Then, E is 13/9, when W=13