Rocket Propulsion - Practice Questions & MCQ

Let us assume a rocket of total initial mass (rocket + fuel) m₀, starts moving upward due to thrust force of fuel jet. Assuming the velocity of fuel jet with respect to the rocket to be u (assumed to be constant for this discussion) in vertically downward direction and mass of jet fuel emerging out of rocket per unit time to be . Let the velocity of rocket after t time of motion be v and the acceleration of the rocket be a in vertically upward direction.

1. Thrust on the rocket

Where F= Thrust

u=velocity of exhaust gas with respect to rocket

m=mass of the rocket at time t

Net force on rocket-

2. Acceleration of Rocket (a)

• If g is neglected then

3. Instantaneous Velocity of Rocket (v)

 If g is neglected then-

4. Burnt speed of Rocket

• It is the speed attained by the rocket when complete fuel gets burnt.

• It is the maximum speed attained by the rocket

• Formula