Aerospace Engineering Gate 2018 Questions with Answer

Ques 27 GATE 2018

An aircraft with a turboprop engine produces a thrust of 500 N and flies at 100 m/s If the propeller efficiency is 0.5, the shaft power produced by the engine is

Ques 28 GATE 2018

An axial compressor that generates a stagnation pressure ratio of 4.0, operates with inlet and exit stagnation temperatures of 300 K and 480 K, respectively. If the ratio of specific heats (γ) is 1.4, the isentropic efficiency of the compressor is

Ques 29 GATE 2018

A rocket has an initial mass of 150 kg. After operating for a duration of 10 s, its final mass is 50 kg. If the acceleration due to gravity is 9.81 m/s² and the thrust produced by the rocket is 19.62 kN, the specific impulse of the rocket is

Ques 30 GATE 2018

An axial compressor rotor with 50% degree of reaction, operates with an axial velocity of 200 m/s. The absolute flow angle at the inlet of the rotor is 22^° with reference to the axial direction. If the axial velocity is assumed to remain constant through the rotor, the magnitude of the relative velocity (in m/s) at the rotor exit is ________ (accurate to one decimal place).

Ques 31 GATE 2018

The relative velocity of air leaving a straight radial impeller of a centrifugal compressor is 100 m/s. If the impeller tip speed is 200 m/s, for a slip free operation, the absolute velocity (in m/s) at the impeller exit is ________ (accurate to one decimal place).

Ques 32 GATE 2018

An aircraft wind tunnel model, having a pitch axis mass moment of inertia (I_yy) of 0.014 kg-m², is mounted in such a manner that it has pure pitching motion about its centre of gravity, where it is supported through a frictionless hinge. If the pitching moment (M) derivative with respect to angle of attack (α), denoted by 'M'_α, is -0.504 N-m/rad and the pitching moment (M) derivative with respect to pitch rate (q), denoted by 'M'_q, is -0.0336 N-m/(rad/s), the damping ratio of the resulting motion due to an initial disturbance in pitch angle is approximately ________ (accurate to three decimal places).

Ques 33 GATE 2018

The tangential velocity component 'V' of a spacecraft, which is in a circular orbit of radius 'R' around a spherical Earth (μ=GM→ gravitational parameter of Earth) is given by the following expression.

Ques 34 GATE 2018

Equation of the trajectory of a typical space object around any planet, in polar coordinates (r, θ) (i.e. a general conic section geometry), is given as follows. (h is angular momentum, μ is gravitational parameter, e is eccentricity, r is radial distance from the planet center, θ is angle between vectors e and r.

Ques 35 GATE 2018

In an elliptic orbit around any planet, the location at which a spacecraft has the maximum angular velocity is

Ques 36 GATE 2018

A spacecraft forms a circular orbit at an altitude of 150 km above the surface of a spherical Earth. Assuming the gravitational parameter, μ=3.986×10¹⁴ m³/s² and radius of earth, R_E=6,400 km. the velocity required for the injection of the spacecraft, parallel to the local horizon, is ________ (accurate to two decimal places).

Ques 37 GATE 2018

Air at 50 kPa pressure and 400 K temperature flows in a duct at Mach 3.0. A part of the flow leaks through an opening on the duct wall into the ambient, where the pressure is 30 kPa. The maximum Mach number achieved in the discharge is ________ (accurate to two decimal places). (Ratio of specific heats of air is γ=1.4).

Ques 38 GATE 2018

Determine the correctness or otherwise of the following statements, [a] and [r]:
[a] A closed-section box beam configuration is used in aircraft wings.
[r] Closed-section box beam configuration is capable of resisting torsional loads.

Ques 39 GATE 2018

A solid circular shaft of diameter d is under pure torsion of magnitude T. The maximum tensile stress experienced at any point on the shaft is