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Can someone please check my answers and possibly help with part c; I don't know where to begin on solving it.

## Homework Statement

A 31000kg jet airliner is flying at 11000m doing 910 km/h.

(a) What is the jet’s gravitational potential energy (GPE) at 11000m? (GPE=0 at sea level)

(b) What is the jet’s kinetic energy (KE)?

(c) If the jet fuel used contains 30.3MJ of energy per litre and the jet engines are 30% efficient at converting the fuel’s

energy, how much fuel is used just to raise the jet’s potential from sea level to 11000m

## The Attempt at a Solution

What is known:

m= 31000kg

h= 11000m

g=9.8m/s

v = 910km/h

e = 30.3 MJ/L

Answer:

a)

Gravitational Potential Energy:

U = mgh

U = 31000 x 9.8 x 11000

U = 3341800000 J = 3.3 x 10^9 J

b)

K = 1/2 mv^2

K = 1/2 31000 x 910000^2

K = 12835550000000000 = 1 x 1016 J

c) I have no idea where to start with this one!

Thanks, any help is greatly appreciated!