Answer
$F_{max}=10. N$
Work Step by Step
To find the maximum force, use the equation $$a_{max}=A\omega ^2$$ and the equation for force $F=ma$ to get $$F_{max}=Am\omega ^2$$ To find the value of omega, use the relation $$\omega=\frac{2\pi}{T}$$ Substitute the known value of $T=0.20s$ to get an omega value of $$\omega=\frac{2\pi}{0.20s}=31.4rad/s$$ Substituting known values of $A=0.085m$, $\omega=31.4rad/s$, and $m=0.12kg$ to get an $F_{max}$ value of $$F_{max}=(0.085m)(0.12kg)(31.4rad/s)^2=10.0 N$$