Figure $3-18/19$ Full Alternative Text

$*3-20.$ The $10-$lb weight is supported by the cord AC and roller and by the spring that has a stiffness of $\backslash ($ k$=10\backslash$mathrm$\{$lb$\}/\backslash$mathrm$\{$in$\}\backslash ).$ and an unstretched length of $\backslash (12\backslash$mathrm$\{$in$\}\backslash ).$ Determine the distance $\backslash ($ d $\backslash )$ to maintain equilibrium.

$3-21.$ The $10-$lb weight is supported by the cord $\backslash ($ A C $\backslash )$ and roller and by the spring. If the spring has an unstretched length of $8$ in$.,$ and the weight is in equilibrium when $\backslash ($ d$=4\backslash )$ in$.,$ determine the stiffness $\backslash ($ k $\backslash )$ of the spring.

Probs. $3-20/21$