A solid block of $2.0 \: kg$ mass slides steadily at a velocity $V$ along a vertical wall as shown in the figure below. A thin oil film of thickness $h=0.15 \: mm$ provides lubrication between the block and the wall. The surface area of the face of the block in contact with the oil film is $0.04 \: m^2$. The velocity distribution within the oil film gap is linear as shown in the figure. Take dynamic viscosity of oil as $ 7 \times 10^{-3} \: Pa-s$ and acceleration due to gravity as $10 \: m/s^2$. Neglect weight of the oil. The terminal velocity $V$ (in $m/s$) of the block is ______ (correct to one decimal place)
