How Is Velocity Calculated for a Two-Stage Rocket?

In summary, the conversation discusses a two-stage rocket with different exhaust velocities for each stage, external gravitational acceleration, and masses of engines, tanks, and fuel for both stages. The first stage burns for 10 seconds and is then ejected, while the second stage burns for 5 seconds. The questions ask about the speed of the second stage/payload combination at the end of the second stage burn and the difference in speed if all the fuel was burned in the first stage in 15 seconds. The relevant equations are also mentioned.
  • #1
engineertech0
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Homework Statement



In a two-stage rocket, the exhaust velocity for the first stage burn is 3000 m/s and for the second stage burn is 3000 m/s. Assume that during the entire sequence of burns the rocket is still near enough to the surface of the Earth to approximate the external gravitational acceleration as 9.8m/s^2 , and ignore air resistance. The mass of the first stage engine and tanks is 2000kg. The mass of the fuel held in the first stage is 4000kg. The first stage fuel burns in 10 seconds. The first stage is then ejected. The mass of the second stage engine, tanks, and payload is 2000kg. The mass of the fuel held in the second stage is 2000kg. The second stage fuel burns in 5 seconds. (The second stage tanks remain attached to the payload when empty.) (a) At what speed is the second stage/payload combination moving at the end of the second stage burn? (b) How much faster is this than the speed if all the 6000kg fuel were burned in the first stage in 15 seconds with the same exhaust velocity (3000m/s) and the entire 4000kg assembly of the empty rocket remained in one piece?


Homework Equations



(d=v*t) (v=d/t)

The Attempt at a Solution

 
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  • #2
What have you tried so far and where are you stuck?

Do you know how to calculate speed change for a single-stage rocket (hint: rocket equation)?
 

FAQ: How Is Velocity Calculated for a Two-Stage Rocket?

What is a 2 Stage Rocket Velocity?

A 2 stage rocket velocity is the speed at which a rocket travels during its flight, taking into account the acceleration and deceleration caused by its two stages.

What are the two stages of a 2 Stage Rocket Velocity?

The two stages of a 2 stage rocket velocity are the boost phase and the coast phase. During the boost phase, the rocket's engines are firing and it is accelerating. During the coast phase, the engines are no longer firing and the rocket is traveling at a constant velocity.

How is the velocity of a 2 Stage Rocket calculated?

The velocity of a 2 stage rocket is calculated by taking into account the rocket's mass, the force of its engines, and the resistance of the air. This calculation is known as the rocket equation and is used to determine the rocket's final velocity.

Why is a 2 Stage Rocket used over a single stage rocket?

A 2 stage rocket is used over a single stage rocket because it allows for greater speed and distance. By having two stages, the rocket can shed unnecessary weight (such as fuel tanks and engines) as it ascends, making it more efficient and allowing it to reach higher velocities.

What factors can affect the velocity of a 2 Stage Rocket?

The velocity of a 2 stage rocket can be affected by several factors, including the mass and design of the rocket, the efficiency of the engines, the amount of fuel and oxidizer, and external forces such as air resistance and gravity. Any changes to these factors can impact the rocket's velocity during its flight.

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