Understanding Physics Impulse: Integrated vs Average

In summary, the conversation discusses the concept of impulse in physics and how it is measured using the area under a force versus time curve. It is mentioned that calculating impulse from a change in velocity is not as accurate as using the integrated impulse. The conversation also includes a thought experiment involving a model rocket and a link to a page with an example of an impulse curve. It is noted that the integral of the curve with a spike will have a greater area and cause a greater change in momentum.
  • #1
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I have a question about physics in real life. Other than the fact that the area under a force versus time curve is a more accurate way to measure impulse because it's not an average like calculating impulse from a change in velocity is, is there any other reason that the integrated impulse would differ from the average impulse? Please let me know if I have phrased this oddly and you need clarification to answer my question. Thank you!
 
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  • #2


As a thought experiment, you may go to this page:

http://www.nar.org/SandT/NARenglist.shtml [Broken]

Open the pdf file for the Estes A10 engine and note the impulse is the area under the curve on the second page. Draw this impulse as an average (rectangle) and the big spike goes away, which is necessary to accelerate a model rocket up to stable velocity while on the launch rail. Both curves have the same total value if you take an impulse integral! The integral of the curve with the spike will accumulates greater impulse (area) in less time initially, causing a greater change in momentum in that region.
 
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  • #3


Hello,

Thank you for your question about understanding physics impulse and the difference between integrated and average values. The area under a force versus time curve does indeed provide a more accurate measure of impulse because it takes into account the varying force over time, rather than just the average force.

In addition to this, there are a few other reasons why the integrated impulse may differ from the average impulse. One reason is that the integrated impulse takes into account the direction of the force, whereas the average impulse does not. This means that if the force is changing direction during the time interval, the integrated impulse will be affected, while the average impulse will remain the same.

Another reason is that the integrated impulse considers the entire time interval, while the average impulse only considers the change in velocity during that time interval. This means that if there are any changes in velocity outside of the specified time interval, the integrated impulse will take them into account, while the average impulse will not.

I hope this helps clarify the difference between integrated and average impulse. Please let me know if you have any further questions or need clarification on anything I have mentioned. Physics can be a complex subject, so it's always good to ask for clarification when needed. Thank you.
 

1. What is the difference between integrated and average impulse?

Integrated impulse refers to the total change in momentum over a certain period of time, while average impulse is the average change in momentum per unit of time.

2. How do you calculate integrated impulse?

To calculate integrated impulse, you need to first find the area under the force-time graph. This can be done by calculating the integral of force with respect to time.

3. What is the relationship between integrated impulse and average force?

The average force applied to an object is equal to the integrated impulse divided by the duration of the force. In other words, average force is the rate at which integrated impulse is applied.

4. Can you give an example of integrated and average impulse?

Imagine a basketball player dribbling a ball. The integrated impulse would be the total change in momentum of the ball as it bounces off the ground and the player's hand. The average impulse would be the average change in momentum per bounce.

5. How does understanding integrated and average impulse contribute to our understanding of physics?

Understanding integrated and average impulse is important in many aspects of physics, including collisions, rocket propulsion, and sports. It helps us calculate the effects of forces on objects and predict their motion.

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