ME GATE 2011 - Online Test

Q1. A cubic casting of 50mm side undergoes volumetric solidification shrinkage and volumetric solid contraction of 4% and 6% respectively. No. riser is used. Assume uniform cooling in all directions. The side of the cube after solidification and contraction is 
Answer : Option A
Explaination / Solution:

Volumetric solidification shrinkage and volumetric solid contraction cause decrease in dimensions. 
Volume of cube = 503 = 125000 mm3
After considering both the allowances 
V = 125000 × 0.96 × 0.94 = 112800mm3


Q2. A column has a rectangular cross-section of 10mm x 20mm and a length of 1m. The slenderness ratio of the column is close to
Answer : Option B
Explaination / Solution:
No Explaination.


Q3. The crank radius of a single–cylinder I. C. engine is 60mm and the diameter of the cylinder is 80mm. The swept volume of the cylinder in cm3 is 
Answer : Option D
Explaination / Solution:

Stroke of the cylinder l = 2r = 2 × 60 = 120mm
Swept volume = (π/4)d2 × I = (π/4) × 802 × 120 = 603 cm3 

Q4. The variable cost (V) of manufacturing a product varies according to the equation V= 4q, where q is the quantity produced. The fixed cost (F) of production of same product reduces with q according to the equation F = 100/q. How many units should be produced to minimize the total cost (V+F)?
Answer : Option A
Explaination / Solution:

Checking with all options in formula: (4q+100/q) i.e. (V+F). Option A gives the minimum cost.

Q5. Match the following criteria of material failure, under biaxial stresses σ1 and σ2 and yield stress σy , with their corresponding graphic representations : 
P. Maximum-normal-stress criterion             L. 
Q. Maximum-distortion-energy criterion      M. 
R. Maximum-shear–stress criterion             N. 
Answer : Option C
Explaination / Solution:
No Explaination.


Q6. A thin cylinder of inner radius 500mm and thickness 10mm is subjected to an internal pressure of 5MPa. The average circumferential (hoop) stress in MPa is
Answer : Option B
Explaination / Solution:

Given Data: p = 5MPa; d = 1000mm; t = 10mm 
Hoop stress = pd/2t = 250MPa

Q7. A pump handling a liquid raises its pressure from 1 bar to 30 bar. Take the density of the liquid as 990 kg /m3. The isentropic specific work done by the pump in kJ/kg is 
Answer : Option D
Explaination / Solution:

Work done by the pump =  

Q8. A torque T is applied at the free end of a stepped rod of circular cross-sections as shown in the figure. The shear modulus of the material of the rod is G. The expression for d to produce an angular twist θ at the free end is 


Answer : Option B
Explaination / Solution:

Angular twist at the free end


Q9. A spherical steel ball of 12mm diameter is initially at 1000K. It is slowly cooled in a surrounding of 300K. The heat transfer coefficient between the steel ball and the surrounding is 5W /m2 K . The thermal conductivity of steel is 20W /mK . The temperature difference between the centre and the surface of the steel ball is 
Answer : Option D
Explaination / Solution:

Bi = hL/K = 5 ×0.002/20 = 0.0005
For the given condition the Biot number tends to zero, that means conduction resistance is far less than convection resistance. Therefore temperature between the centre and surface is very small.

Q10. Two identical ball bearings P and Q are operating at loads 30kN and 45kN respectively. The ratio of the life of bearing P to the life of bearing Q is
Answer : Option B
Explaination / Solution: