Problem $1.$ In case $1$ study, it states that when the virtual center is nearly under the crank $($shown in Figure $4$a$)$ the moment arm of the rear stay is much shorter than when the suspension is deflected $($in Figure $4$b$).$ Please draw and label the moment arm of the rear stay in Figure $4$a and the moment of arm the rear stay in Figure $4$b$.$ Tips: Identify the rear stay of the bike first in each figure. And create and label a solid black$-$color line to represent the rear stay of the bike if you can not locate the rear stay of the bike. The line representing the moment of arm should be perpendicular to the line of rear stay.