Find the Mach number when an aeroplane is flying at 900 km/ hour through still air having a pressure of 8 $N/cm^2$ and temperature -$15^0$ C. take k=1.4 and R= 287 J/kg K. Calculate the pressure, density and temperature of air at stagnation point on the nose of plane.

Given :

$ \begin{aligned} \text{v} =900 \space {Km}/{P h} &=\frac{900 \times 1000}{60 \times 60} \\ &= 250 \space {m} / {s} \\ \text {Pressure of a air }\left(P \right) &=8 \space {N} /{cm}^{2} \\&=8 \times 10^{4} \space{N} / {m}^{2} \\ T =15^{\circ}{C} &=15+273=288\space {K} \\ K &=1.4\\ \end{aligned} $

Now …