Answer
$(a)$
The slope represents rate of change of the stretch length with respect to weight.
The $s$-intercept represents actual length of the spring without any weight attached.
$(b)$
$4$ $inches$
Work Step by Step
$(a)$
The slope represents rate of change of the stretch length $s$ with respect to $w$ weight.
The $s$-intercept happens when $w=0$, which represents actual length of the spring without any weight attached.
$(b)$ $s=0.3w+2.5$
If the weight is $w=5lb$, then we have:
$s=0.3\times5+2.5=1.5+2.5=4in$
