Answer:
2324 J
Explanation:
The formula for work is:

where
is the force applied, and
is the distance moved, in this case 
and we need to find 
Since the crate is not moving up or down, we conclude that the <u>normal force must be equal to the weight </u>of the object:

where
is the normal force and
is the weight, which is:
, where g is the gravitational acceleration
and
is the mass
.
---------
Thus the normal force is:

Now, the force due to the friction is defined as:

where
is the coefficient of friction, 
So, for the crate to move, the force applied must be equal to the frictional force:

And now that we know the force we can calculate the work:

substituting known values:
