Answer:
[012] :
Here x component is zero. That is why this is in y- z plane
[721] :
This is in all three plane .It means it is in space.
[110] :
Here z component is zero.
That is why this is in x -y plane
From the cubic unit directions we can easily understand all given directions [012], [721], [110].
Answer:
a)27.9%
b)
Explanation:
Given that
Fuel energy content = 73.1 MJ/kg
Useful power = 17.4 KW
Heat rejection rate = 44.8 KW
From first law of thermodynamics
Heat addition rate =Heat rejection rate + Power out put
Now by putting the values in the above formula
Heat addition rate = 44.8 + 17.4
Heat addition rate =62.2 KW
We know that efficiency is given as follows

So


So the efficiency is 27.9%.
Now to find usage rate of fuel
Lets take usage rate is 
Fuel energy content x usage rate of fuel = Heat addition rate
Now by putting the values


Tell me why i got this question got it right and now won’t remember but i’ll get back at you when i remember