Answer
$\mu_s=0.128, \mu_k=0.0850$
Work Step by Step
To find the maximum force of static friction, use the formula $$F_{s,max}=\mu_smg$$ Solving for $\mu_s$ yields $$\mu_s=\frac{F_{s,max}}{mg}$$ Substituting known values of $F_{s,max}=2.25N$, $m=1.80kg$, and $g=9.80m/s^2$ yields a coefficient of static friction of $$\mu_s=\frac{2.25N}{(1.80kg)(9.80m/s^2)}=0.128$$ To find the maximum force of kinetic friction, use the formula $$F_{k,max}=\mu_kmg$$ Solving for $\mu_s$ yields $$\mu_k=\frac{F_{k,max}}{mg}$$ Substituting known values of $F_{k,max}=1.50N$, $m=1.80kg$, and $g=9.80m/s^2$ yields a coefficient of static friction of $$\mu_s=\frac{1.50N}{(1.80kg)(9.80m/s^2)}=0.0850$$
