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

1. Nov 12, 2008

### cantgetno

1. The problem statement, all variables and given/known data
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?

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

Power=mass x velocity

3. 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

2. Nov 12, 2008

### LowlyPion

Re: Power

There's no gravity?

3. Nov 12, 2008

### cantgetno

Re: Power

oh of course

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

is that it?

4. Nov 12, 2008

### LowlyPion

Re: Power

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

In this case it is P = m*g *v

5. Nov 12, 2008

### cantgetno

Re: Power

OK i get what you mean

so its:

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

thank you lots

6. Nov 12, 2008

### LowlyPion

Re: Power

There you go.

Cheers.