Calculating Exhaust Gas Speed for a 4200kg Rocket Launch

In summary, the problem involves finding the exhaust speed of a rocket accelerating at 4.0g with a mass of 4200kg and a gas ejection rate of 28kg/s. After some initial miscalculations, it was determined that the rocket must overcome 1g and the correct equation to use is Fthrust=mv2-mv1/t2-t1. The final answer is 7400m/s.
  • #1
pbumper1
6
0

Homework Statement


A 4200kg rocket is to be accelerated at 4.0g at take-off from the Earth.
If the gases can be ejected at a rate of 28 kg/s, what must be their exhaust speed?

Homework Equations



Fthrust=mv2-mv1/t2-t1

The Attempt at a Solution



Multiplied 4200kgx4x9.8/28kg/s=-5900
 
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  • #2
Your work seems fine to me. Do you have any specific questions on this problem?
 
  • #3
The answer is wrong and don't understand why it is?
 
  • #4
I figured it out for future reference, since the rocket has to overcome 1g you add it to the 4g. You use the same equation. 4200x5x9.8/28=7400m/s
 
  • #5
pbumper1 said:
I figured it out for future reference, since the rocket has to overcome 1g you add it to the 4g. You use the same equation. 4200x5x9.8/28=7400m/s


Good catch! Nice job.:smile:
 

Related to Calculating Exhaust Gas Speed for a 4200kg Rocket Launch

1. How is exhaust gas speed measured?

Exhaust gas speed is typically measured using a flow meter, which measures the volume of gas passing through a specific point in a given time. The most commonly used unit of measurement is cubic feet per minute (CFM).

2. What factors affect the speed of exhaust gas?

The speed of exhaust gas can be affected by a number of factors, including the engine size, power output, air-to-fuel ratio, and exhaust system design. Other factors such as altitude, temperature, and humidity can also have an impact on exhaust gas speed.

3. How does exhaust gas speed impact engine performance?

The speed of exhaust gas can have a significant impact on engine performance. A higher exhaust gas speed can help improve the scavenging process, which removes the spent gases from the combustion chamber and allows for a more efficient intake of fresh air and fuel. This can result in improved power output and fuel efficiency.

4. What are the potential dangers of high exhaust gas speed?

High exhaust gas speed can lead to backpressure in the exhaust system, which can reduce engine performance and potentially cause damage to engine components. It can also increase the risk of exhaust leaks and emission of harmful pollutants into the environment.

5. How can exhaust gas speed be controlled?

Exhaust gas speed can be controlled through various methods such as by adjusting the engine's air-to-fuel ratio, using a tuned exhaust system, and implementing exhaust gas recirculation (EGR) systems. Proper maintenance and regular tune-ups can also help maintain a healthy exhaust gas speed.

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