Solution :
Given :
Rectangular wingspan
Length,L = 17.5 m
Chord, c = 3 m
Free stream velocity of flow,
= 200 m/s
Given that the flow is laminar.



So boundary layer thickness,


= 0.0024 m
The dynamic pressure, 


The skin friction drag co-efficient is given by


= 0.00021


= 270 N
Therefore the net drag = 270 x 2
= 540 N
<u>Answer:</u>
Mass of C in 3.40 g of HCN =1.51 gram.
<u>Explanation:</u>
Mass of sample of HCN = 7.99 g
Mass of H in 7.99 g of HCN = 0.296 g
Mass of N in 7.99 g of HCN = 4.14 g
Mass of C in 7.99 g of HCN = (7.99-0.296-4.14) = 3.554 g
Now mass of HCN = 3.40 g
Mass of C in 3.40 g of HCN = 
So mass of C in 3.40 g of HCN =1.51 gram.