Observe the figure :
\The engine is approximately
above the top of the fuel tank.
Weight of the diesel fuel is approximately
.
Since the engine is approximately
above the top of the fuel tank the volume can be considered as Volume,
.
The force is calculated by
.
The force of pushing one rectangle with depth
is
.
.
The work done can be calculated by using the formula
.
Since the height of the engine is
above the top of the fuel tank the limit ranges from
to
.
.
, so write in the terms of
.


Apply integration :
\
The work done by the fuel pump in raising the fuel tank of fuel to the level of the engine is
.