A solid propellant of density $1800 \mathrm{~kg} / \mathrm{m}^{3}$ has a burning rate law $r=6.65 \times 10^{-3} p^{0.45} \mathrm{~mm} / \mathrm{s}$, where $p$ is pressure in Pascals. It is used in a rocket motor with a tubular grain with an initial burning area of $0.314 \mathrm{~m}^{2}$. The characteristic velocity is $1450 \mathrm{~m} / \mathrm{s}$. What should be the nozzle throat diameter to achieve an equilibrium chamber pressure of 50 bar at the end of the ignition transient? (A) $35 \mathrm{~mm}$ (B) $38 \mathrm{~mm}$ (C) $41 \mathrm{~mm}$ (D) $45 \mathrm{~mm}$

Question ID - 156246 :- A solid propellant of density $1800 \mathrm{~kg} / \mathrm{m}^{3}$ has a burning rate law $r=6.65 \times 10^{-3} p^{0.45} \mathrm{~mm} / \mathrm{s}$, where $p$ is pressure in Pascals. It is used in a rocket motor with a tubular grain with an initial burning area of $0.314 \mathrm{~m}^{2}$. The characteristic velocity is $1450 \mathrm{~m} / \mathrm{s}$. What should be the nozzle throat diameter to achieve an equilibrium chamber pressure of 50 bar at the end of the ignition transient? (A) $35 \mathrm{~mm}$ (B) $38 \mathrm{~mm}$ (C) $41 \mathrm{~mm}$ (D) $45 \mathrm{~mm}$

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(B) $38 \mathrm{~mm}$

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A bipropellant liquid rocket motor operates at a chamber pressure of 40 bar with a nozzle throat diameter of $50 \mathrm{~mm}$. The characteristic velocity is $1540 \mathrm{~m} / \mathrm{s}$. If the fuel-oxidizer ratio of the propellant is $1.8,$ and the fuel density is $900 \mathrm{~kg} / \mathrm{m}^{3},$ what should be the minimum fuel tank volume for a burn time of 8 minutes
(A) $1.65 \mathrm{~m}^{3}$
(B) $1.75 \mathrm{~m}^{3}$
(C) $1.85 \mathrm{~m}^{3}$
(D) $1.95 \mathrm{~m}^{3}$