A bathroom scale has a spring that is compressed by $1\mathrm{.}50$ cm when a $180$ kg person stands on the scale. Assuming the spring is described by Hooke's law, find its force constant $($in N$/$m$).$

N$/$m

$($b$)$

How much $($in mm$)$ would it be compressed if a $87\mathrm{.}0$ kg person stands on the scale in an elevator that is accelerating upward at $1\mathrm{.}25$ m$/$s$2?$

mm