For a circular trajectory of a satellite around the earth, the centrifugal forces must balance the ______

lift forces

drag forces

propulsive forces

gravitational forces

Correct Answer : gravitational forces

Explanation : The centrifugal forces should be equal to the gravitational forces for a satellite revolving around the earth in a circular orbit. If m denotes the satellite mass, u_s denotes the satellite velocity, and R represents the radius of the orbit, then mu_s²/R = mg.

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.