Average Power Output for 260000 kg Jet at 9200m Altitude

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Homework Help Overview

The problem involves calculating the average power output of a jet after reaching a cruising altitude of 9200 meters, with a mass of 260000 kg and a speed of 235 m/s. The context includes considerations of kinetic and potential energy in the calculation.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the initial attempt to calculate power output using only kinetic energy, questioning the omission of potential energy in the work equation.

Discussion Status

Some participants have pointed out the need to include potential energy in the calculations, suggesting a revised approach that combines both kinetic and potential energy to determine the total work done.

Contextual Notes

The discussion reflects on the assumptions made in the problem, particularly the neglect of friction and the need to account for changes in potential energy during the jet's ascent.

spockjones20
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Homework Statement



620 seconds after starting its take-off, a 260000 kg jet reaches its cruising altitude of 9200 meters and flies with a speed of 235 m/s. Neglecting friction, what has been the average power output of the engines?

Homework Equations



ΔKE = Work
Power = Work/time

The Attempt at a Solution



Initial KE = 0
Final KE = .5*260000*235^2 = 7179250000
Power = 7179250000/620 = 11579435.48 Watts

Can someone see an issue with what I am trying to do here? I tried to type in this answer but apparently it is wrong.
 
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spockjones20 said:

Homework Statement



620 seconds after starting its take-off, a 260000 kg jet reaches its cruising altitude of 9200 meters and flies with a speed of 235 m/s. Neglecting friction, what has been the average power output of the engines?

Homework Equations



ΔKE = Work
Power = Work/time

The Attempt at a Solution



Initial KE = 0
Final KE = .5*260000*235^2 = 7179250000
Power = 7179250000/620 = 11579435.48 Watts

Can someone see an issue with what I am trying to do here? I tried to type in this answer but apparently it is wrong.

I haven't checked your math, but I can see you left out the change in potential energy.
 
Ok. Would that go into the work equation?
 
spockjones20 said:
Ok. Would that go into the work equation?

I believe so.

Try this: ΔKE + ΔPE = Work

and see what happens.
 

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