A double acting hydraulic cylinder has a bore of $200 \mathrm{~mm}$ with a piston rod of $140 \mathrm{~mm}$ diameter. The extend speed of the piston is $80 \mathrm{~mm} \mathrm{~s}^{-1}$. If the flow rate of oil during retraction is same as that of the extending, the retract speed of the piston in $\mathrm{mm} \mathrm{s}^{-1}$ is____________
A double acting hydraulic cylinder has a bore of $200 \mathrm{~mm}$ with a piston rod of $140 \mathrm{~mm}$ diameter. The extend speed of the piston is $80 \mathrm{~mm} \mathrm{~s}^{-1}$. If the flow rate of oil during retraction is same as that of the extending, the retract speed of the piston in $\mathrm{mm} \mathrm{s}^{-1}$ is____________