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ESE Mechanical 2015 Paper 1: Official Paper

Option 3 : 0.75

CT 3: Building Materials

3235

10 Questions
20 Marks
12 Mins

**Concept:**

**Mach number: **It is defined as the ratio of the velocity of flow to the velocity of sound in that medium.

\(M = \frac{V}{C}\)

Speed of sound is given as \(C = \sqrt {\gamma RT} \)

__Calculation:__

Given, V = 300 m/s, γ = 1.6, R = 0.25 kJ/kg K, T = 127°C = 400 K

\(C = \sqrt {\gamma RT} = \sqrt {1.6 \times 250 \times 400} = \;400\;m/s\)

\(M = \frac{V}{C} = \frac{{300}}{{400}} = 0.75\)