Which of these describes a challenge that the engineer of a high-altitude airplane would need to consider?
A. More fuel is used at higher altitudes.
B. The airplane may succumb to the power of gravity as lift
decreases at higher altitudes.
C. The airplane may need a heat shield for protection from sonic
booms.
O D. The airplane will create more drag at higher altitudes than lower
altitudes.

I think its (B)

Explanation:

as when the air thins out at higher elevations, your lift decreases so at some point, the plane cant produce enough lift to overcome gravity.

answer : (a) volume of the gas = 8.67 ×   l

                (b) second virial coefficient b = -1.21226 l/mole

solution :   given,     t = 300k

                                p = 20atm

                                z = 0.86

                                n = 8.2 mmoles = 8.2 × moles

                                r =   0.082 l atm/k/mol

        find,     (a) volume of gas   and (b) second virial coefficient b at 300k.

formula used :            

                          and            

(a)            

                    = \times 0.082\times 300}{20}[/tex]

                    = 8.67 ×   l

(b)      

                    = (0.00867-1) × 8.659

                    = - 8.5839 l/mole