Air at standard sea$-$level pressure $(p101k\frac{N}{m^2})$ has a temperature of $4C.$ What is the density of the air?

A board $1m$ by $1m$ that weighs $20N$ slides down an inclined ramp $($slope $22)$ with a velocity of $0\mathrm{.}02\frac{m}{s}.$ The board is separated from the ramp by a thin film of oil with a viscosity of $0\mathrm{.}05N.\frac{s}{m^2}.$ Neglecting the edge effects, calculate the space between the board and the ramp.