Aerospace Engineering Gate 2018 Questions with Answer

Ques 14 GATE 2018


The solution of the differential equation d2y/dx2+3dy/dx=0. given that y=0 and dy/dx=1 at x=0 is

A

x(1−e−3x)

B

1/3(1−e−3x)

C

1/3(1+e−3x)

D

1/3xe−3x/2


(b) is the correct answer.

Ques 15 GATE 2018


The relation between pressure (p) and velocity (V) for a steady, isentropic flow at two points along a streamline is, (c is a constant)

A

c(p2γ−p1γ)=V12/2−V22/2

B

c(p2γ/(γ−1)−p1γ/(γ−1))=V12/2−V22/2

C

c(p2(γ−1)/γ−p1(γ−1)/γ)=V12/2−V22/2

D

c(p2γ−1−p1γ−1)=V12/2−V22/2


(c) is the correct answer.

Ques 16 GATE 2018


Consider the vector field v=−(y/r2)î+(x/r2)j; where r=√(x2+y2) The contour integral ∮v⋅ds, where ds is tangent to the contour that encloses the origin, is ________ (accurate to two decimal places).


(6.25 to 6.35) is the correct answer.

Ques 17 GATE 2018


The magnitude of the x-component of a unit vector at the point (1, 1) that is normal to equi-potential lines of the potential function φ(r)=1/(r2+4), where r=√(x2+y2) is ________ (accurate to two decimal places).


(0.68 to 0.73) is the correct answer.

Ques 18 GATE 2018


A jet aircraft is initially flying steady and level at its maximum endurance condition. For the aircraft to fly steady and level, but faster at the same altitude, the pilot should

A

increase thrust alone.

B

increase thrust and increase angle of attack.

C

increase thrust and reduce angle of attack.

D

reduce angle of attack alone.


(c) is the correct answer.

Ques 19 GATE 2018


The pilot of a conventional airplane that is flying steady and level at some altitude, deflects the port side aileron up and the starboard aileron down. The aircraft will then

A

pitch, nose up.

B

roll with the starboard wing up.

C

pitch, nose down.

D

roll with the port wing up.


(b) is the correct answer.

Ques 20 GATE 2018


An airplane requires a longer ground roll to lift-off on hot summer days because

A

the thrust is directly proportional to free-stream density.

B

the thrust is directly proportional to weight of the aircraft.

C

the lift-off distance is directly proportional to free-stream density.

D

the runway friction is high on hot summer days.


(a) is the correct answer.

Ques 21 GATE 2018


The highest limit load factor experienced by a civil transport aircraft is in the range

A

0.0-2.0

B

2.0-5.0

C

5.0-8.0

D

8.0-10.0


(b) is the correct answer.

Ques 22 GATE 2018


A statically-stable aircraft has a C=5 (where the angle of attack, α, is measured in radians). The coefficient of moment of the aircraft about the center of gravity is given as CM,c.g=0.05−4α The mean aerodynamic chord of the aircraft wing is 1 m. The location (positive towards the nose) of the neutral point of the aircraft from the center of gravity is ________ (in m, accurate to two decimal places).


(-0.81 to -0.79) is the correct answer.

Ques 23 GATE 2018


An aircraft with a gross weight of 2000 kg, has a speed of 130 m/s at sea level, where the conditions are: 1 atmosphere (pressure), 288 K (temperature), and 1.23 kg/m3 (density). The speed (in m/s) required by the aircraft at an altitude of 9000 m, where the conditions are: 0.31 atmosphere, 230 K, and 0.47 kg/m3 to maintain a steady, level flight is ________ (accurate to two decimal places).


(209.00 to 211.00) is the correct answer.

Ques 24 GATE 2018


A pitot probe on an aircraft in a steady, level flight records a pressure of 55,000 N/m2 The static pressure and density are 45,280 N/m2 and 0.6 kg/m3, respectively. The wing area and the lift coefficient are 16 m2 and 2, respectively. The wing loading (in N/m2 on this aircraft is ________ (accurate to one decimal place).


(18000 to 19440) is the correct answer.

Ques 25 GATE 2018


Gross weight of an airplane is 7000 N, wing area is 16 m2, and the maximum lift coefficient is 2.0. Assuming density at the altitude as 1.23 kg/m3, the stall speed (in m/s) of the aircraft is ________ (accurate to two decimal places).


(18.80 to 18.90) is the correct answer.

Ques 26 GATE 2018


An aircraft with a turbojet engine flies at a velocity of 100 m/s. If the jet exhaust velocity is 300 m/s, the propulsive efficiency of the engine, assuming a negligible fuel-air ratio, is

A

0.33

B

0.50

C

0.67

D

0.80


(b) is the correct answer.

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