Calculating Average Thrust Force for Airplane Take-off

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Homework Help Overview

The discussion revolves around calculating the average thrust force required for an airplane to take off, given its take-off speed of 250 mi/h and weight of 110,000 Kg. Participants are exploring the relationship between weight, thrust, and the units of measurement involved.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to clarify the meaning of units (mi/h) and how they relate to the problem. There is discussion about the formulas for weight and thrust, with some questioning whether the average thrust force is equivalent to net force. Others express confusion about the relevance of the take-off speed in the calculations.

Discussion Status

The conversation is ongoing, with participants providing insights into the definitions of weight and thrust. Some have raised concerns about the clarity of the question and the potential omission of necessary information, such as runway length. There is no explicit consensus on how to proceed with the calculations.

Contextual Notes

Some participants note that the question may be poorly worded, highlighting the distinction between mass and weight. There is also mention of the possibility that extraneous information is included to complicate the problem.

BlueOwl
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Homework Statement



The take-off speed of a given airplane is 250 mi/h. If the take-off weight is 110,000 Kg, what is average the thrust force exerted by the engines?


Homework Equations



w=mg ,F=ma , F=mW

The Attempt at a Solution



the mi/h confuses me and I don't know which formula to use and is the average thrust force the net force?
 
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mi/h is miles per hour. Think of it as distance/time, ie, velocity.

W(eight) is a force; it is your mass multiplied by the acceleration of the body you are standing on. On this case it is earth; so acceleration due to g(ravity) = 9.81 m/s.

I hope it is clear then that the Weight force F = mW of the aircraft is

9.81 * 110000 = 1,079,100 N, or 1079 kN.

Which I am pretty sure must be the answer...but to be honest the question is rather poorly written. Is that how it appears at in the textbook/whatever? Planes don't take off vertically because of the horizontal force applied by the Engines, as you probably well already know...

Let me know if there's anything you didn't get or would like clearing up:)
 
rabbitweed said:
mi/h is miles per hour. Think of it as distance/time, ie, velocity.

W(eight) is a force; it is your mass multiplied by the acceleration of the body you are standing on. On this case it is earth; so acceleration due to g(ravity) = 9.81 m/s.

I hope it is clear then that the Weight force F = mW of the aircraft is

9.81 * 110000 = 1,079,100 N, or 1079 kN.

Which I am pretty sure must be the answer...but to be honest the question is rather poorly written. Is that how it appears at in the textbook/whatever? Planes don't take off vertically because of the horizontal force applied by the Engines, as you probably well already know...

Let me know if there's anything you didn't get or would like clearing up:)

where does the 250 miles per hour come into the formula though? or it doesn't ?
 
I suspect that you left out some info? Perhaps the length of the runway?

And this certainly is a poorly worded question. For instance, kg is a unit of mass, not weight. If this is verbatim out of your physics book, then I feel sorry for you, and I hope we can be of some service.
 
BlueOwl said:
where does the 250 miles per hour come into the formula though? or it doesn't ?

It doesn't seem to at all. This is rather common in physics questions; give you quantities you don't need to confuse you. But with that question it really is hard to tell what on Earth they're asking.

Can I ask; are you doing this for school, or self-study? If the latter I'd be happy to recommend a good textbook.
 

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