GATE

Q. “When she fell down the_________, she received many ___________ but little help.” The words that best fill the blanks in the above sentence are (A) stairs, stares                         (B) stairs, stairs (C) stares, stairs                         (D) stares, stares Ans: stairs, stares

Q. An aircraft wind tunnel model, having a pitch axis mass moment of inertia (Iyy) 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

Q. 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 . Ans: 222.0 to 225.0

Q. 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 22o with reference to the axial direction. If the axial velocity is assumed to remain constant through the rotor, the magnitude of the relative velocity

Q. The components of stress in a body under plane stress condition, in the absence of body forces, is given by: 𝜎𝑥𝑥 = 𝐴𝑥2; 𝜎𝑦𝑦 = 12𝑥2 − 6𝑦2 and 𝜎𝑥𝑦 = 12𝑥𝑦. The coefficient, A, such that the body is under equilibrium is Ans: -6.0 to -6.0

Q. A cantilever beam having a rectangular cross-section of width 60 mm and depth 100 mm, is made of aluminum alloy. The material mechanical properties are: Young’s modulus, E = 73 GPa and ultimate stress, 𝜎𝑢 = 480 MPa. Assuming a factor of safety of 4, the maximum bending moment (in kN-m) that can be

Q. A 1 m long massless cantilever beam oscillates at 2Hz, while a 60 kg mass is attached at the tip of it. The flexural rigidity of the beam (in kN-m2) is (accurate to two decimal places). Ans: 3.10 to 3.20

Q. A thin-walled tube with external radius of 100 mm and wall thickness of 2 mm, is fixed at one end. It is subjected to a compressive force of 1 N acting at a point on the circumference parallel to its length. The maximum normal stress (in kPa) experienced by the structure is Ans: -2.50

Q. 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 Ans: 18.80 to 18.90

Q. The boundary layer thickness at the location of a sensor on a flat plate in an incompressible, laminar flow of air is required to be restricted to 1 mm for an effective measurement. If the flow velocity is 20 m/s with 1 bar pressure, 300 K temperature, and 1.789×10˗5 kg/(m-s) viscosity, the maximum distance