Q. A sand casting process has a mold constant of 2 s/mm2 and solidification exponent of 2. If the solidification time is to be doubled for a given unit volume of material, the corresponding reduction in the cast surface area (in %) is Ans: 28-31 Sol:
A sand casting process has a mold constant of 2 s/mm2 and solidification exponent of 2 Read More »
Q. The heat transfer efficiency in arc welding of a plate using a current of 250 A at 20 V is 90%. The heat required to melt the material is 10 J/mm3. If the cross-sectional area of the weld joint is 30 mm2 and the travel speed is 5 mm/s, the melting efficiency (in %)
Q. A cam is designed to achieve a simple harmonic motion of a flat-faced follower. Starting from the rest, the follower rises to the maximum height of 50 mm at 180˚ of cam rotation as shown in the figure. If the cam rotates at a uniform angular speed of 100 rpm, the speed of the
Q. A thin walled cylindrical pressure vessel with an inside diameter of 300 mm and wall thickness of 3 mm is subjected to an internal gauge pressure of 1.5 MPa. The maximum shear stress (in MPa) at a point located on the inner surface of the pressure vessel is Ans: 37 – 40 Sol:
Q. Considering included angle θ of the thread to be 60˚ using the Best-Wire method, the difference between the effective diameter (E ) and the dimension under the wire (T ) for M10 × 1.0 mm is closest to (A) 0.289 (B) 0.578 (C) 0.867 (D) 0.982 Ans: 0.289 Sol:
Q. A firm, with a production target of 50,000 units/year, has the following data for the selection of a new location for its plant Location Fixed cost (Rs.) Variable costs per unit (Rs.) P 110,000 2 Q 95,000 2.5 R 80,000 3 S 75,000 3.5 The most economical location for the firm is (A) P
Q. A company invests Rs.50 thousand in assets. The initial investment is Rs.30 thousand with two subsequent investments of Rs.10 thousand each at the end of 1st year and 2nd year. The useful life of the assets is 10 years with no salvage value at the end. If the interest rate is 10% and the minimum attractive rate of return (MARR) is
Q. The mean time to repair (MTTR) for a repairable system is 30 minutes. When maintenance time changes from 20 minutes to 40 minutes, the net increase in maintainability is closest to (A) 0.15 (B) 0.25 (C) 0.45 (D) 0.60 Ans: 0.25 Sol:
The mean time to repair (MTTR) for a repairable system is 30 minutes Read More »
Q. A 100 mm long cylindrical workpiece of diameter 50 mm is reduced to 25 mm diameter using extrusion process. The flow curve for the metal has strength coefficient as K = 750 MPa and the strain hardening co-efficient is 0.15. Assuming no friction and no redundant work, the required ram pressure (in MPa) is
Q. In a sine bar, let h denote height of slip gauge and l be the distance between the rollers. The relationship between error in angular measurement ( dq ) and errors in the slip gauge combination ( dh ) and in the spacing of the rollers ( dl ) is Ans: Sol: h =
