Keeping the system inert mass constant, which of the following changes will not result in flight velocity increment?

Better nozzle cooling

Higher chamber pressure

Use of better propellants

A more favorable nozzle area ratio

Correct Answer : Better nozzle cooling

Explanation : Because doing any of these except better nozzle cooling will result in better Isp. Velocity increment is directly proportional to Isp, so more Isp means more velocity increment.

Recently Updated in Rocket Propulsion Questions

For an airplane undergoing a steady pull-up maneuver along a curved flight path of the constant angle of attack, constant pitch rate of 20°/s, and having a radius of curvature of 150 m, determine the flight velocity.

38.33 m/s

47.66 m/s

52.36 m/s

69.42 m/s

Correct Answer : Option (C) : 52.36 m/s

Explaination : Pitch rate q = V/R
Then, V = qR = 20 x π/180 x 150 = 52.36 m/s.

Determine the period of revolution of an artificial satellite in a circular orbit of altitude 350 km.

1.266 hrs

1.395 hrs

1.525 hrs

1.738 hrs

Correct Answer : Option (C) : 1.525 hrs

Explanation : T=2π(R₀+h)^3/2/√μ
= 2×3.14x(6728000)^3/2/(3.986×10¹⁴)
= 1.525 hrs.

Which of the following can be spin-stabilized?

Bullet trains

Artificial satellites

Commercial aircrafts

Unguided rocket projectiles

Correct Answer : Option (D) : Unguided rocket projectiles

Explanation : Unguided rocket projectiles can be given a rotation about its longitudinal axis by means of inclined fins or smaller rocket nozzles to stabilize it. This is an example of spin stabilization.