A projectile is travelling in an air having pressure and temperature as 8.829 N/cm2 and – 2 0C. If the Mach angle is 40 0 then find the Mach number and velocity of projectile. Take γ=1.4 and R=287 J/kg K.

Solution :

Given :

Pressure of air, $ \begin{aligned} \qquad \quad P &=8.829 \mathrm{~N} / \mathrm{cm}^{2}\\ &=8.829 \times 10^{4} \mathrm{~N} / \mathrm{m}^{2} \end{aligned}$

Temperature of air,

$\begin{aligned} \qquad \quad T &=-2^{\circ} \mathrm{C}\\ T &=-2+273=271^{\circ} \mathrm{K} \\ \end{aligned}$

Mach angle, $ \alpha=40^{\circ}$

k=1.4,

R=287 $ \mathrm{~J} / \mathrm{kg}^{\circ}\mathrm {~K}$

The velocity …