What fraction of the engine power is being used for the place to fly

  • Thread starter cantgetno
  • Start date
  • #1
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Homework Statement


When its engine of power 76 kW is generating full power, a small single-engine airplane with mass 660 kg gains altitude at a rate of 2.8 m/s.
What fraction of the engine power is being used to make the airplane climb?

Homework Equations


total power=76x10^3 W
mass=660 kg
dx/dt=velocity=2.8 m/s

Power=mass x velocity

The Attempt at a Solution


(660x2.8)/(76x10^3) x 100 = 2.4% but this is wrong and im not sure where ive gone wrong
 

Answers and Replies

  • #2
LowlyPion
Homework Helper
3,097
5


Homework Statement


When its engine of power 76 kW is generating full power, a small single-engine airplane with mass 660 kg gains altitude at a rate of 2.8 m/s.
What fraction of the engine power is being used to make the airplane climb?

Homework Equations


total power=76x10^3 W
mass=660 kg
dx/dt=velocity=2.8 m/s

Power=mass x velocity

The Attempt at a Solution


(660x2.8)/(76x10^3) x 100 = 2.4% but this is wrong and im not sure where ive gone wrong

There's no gravity?
 
  • #3
23
0


oh of course

660(2.8+9.8)/(76x10^3) x 100 =10.9%

is that it?
 
  • #4
LowlyPion
Homework Helper
3,097
5


oh of course

660(2.8+9.8)/(76x10^3) x 100 =10.9%

is that it?

No. Because Power is Work / time = Force * distance / time

In this case it is P = m*g *v
 
  • #5
23
0


OK i get what you mean

so its:

660x2.8x9.8 / 76x10^3 x 100 = 23.8

thank you lots
 
  • #6
LowlyPion
Homework Helper
3,097
5


OK i get what you mean

so its:

660x2.8x9.8 / 76x10^3 x 100 = 23.8

thank you lots

There you go.

Cheers.
 

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