Which of the following is a reasonable factor of increase for effective exhaust velocity (c) as altitude is increased?

1.5

2.1

3.2

4.5

Correct Answer : 1.5

Explanation : The value of c can increase by a small factor between 1.2 to 1.6 as altitude is increased. Rocket motors produce greater thrust at higher altitudes due to the lower atmospheric pressure.

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.