$*$A spring is used to keep a cover closed as

shown in the diagram. The cover $($green block$)$

has a mass of $500$ g and is held in place by a

spring. The spring is unstretched when vertical

and has a spring constant of $k=100\frac{N}{c}m.$

The coefficient of friction between the cover

and the lid is ${}_s=0\mathrm{.}2.$ Calculate the horizontal

force $(F)$ required to hold the cover fully open.

The tension in a linear spring is $T=ks$ where $s$

is the amount the spring has been stretched

$($equal to its length minus its unstretched

length$).$