For the circular piston shown below $-$ the inside diameter of the cylinder chamber, $D_i=3\mathrm{.}75$ inches; and the outside diameter of the piston, $D_p=3\mathrm{.}5$ inches. The piston moves at a velocity of $4$ feet per second. Assume that the hydraulic fluid in the cylinder surrounding the piston has an kinematic viscosity is $0\mathrm{.}0069f\frac{t^2}{sec}$ and has a specific gravity of $0\mathrm{.}92.$ Determine the force applied to the piston to move the piston $L=20$ inches. $$

$7$ pounds

$14$ pounds

$21$ pounds

$28$ pounds

$35$ pounds