What is the vertical distance of centre of pressure below the centroid of plane area?
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Solution
The vertical distance of centre of pressure below the centroid of plane area will be\(\frac{I_{G}sin^{2}\theta }{A.\bar{h}}\)
In a study to estimate the idle time of a machine, out of 100 random observations, the machine is found idle on 40 observations. If confidence level is 95% and accuracy is ± 5%,then the total random observations required are _________.
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Solution
The value of surface roughness h obtained during the turning operation at a feed f with around nose tool having radius r is given as:
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Solution
Surface roughness (h) = f2⁄8r
where, f = feed, r = radius
Crater wear on the tool always starts at some distance from the tool tip because at that point
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Solution
Crater wear occurs at high temperatures. In crater wear,contacting chips leads to errosion of rake face. The highest temperature of tool can exceed 700°C and occurs at rake face.
A bar of length L tapers uniformly from diameter 1.1D at one end of 0.9D at the other end. The elongation due to axial pull is computed using mean diameter D. The approximate error in computed elongation will be :
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Solution
Match List-I with List-II
List-I List-II
A.Klein’s construction 1.Instaneous centres inlinkages
B.Kennedy’s theorem 2.Relative acceleration of linkages
C.‘D’ Alembert’s principle 3.Mobility of linkages
D.Grubler’s rule 4.Dynamic forces in linkages
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Solution
Klein’s construction= Relative acceleration of linkages
Kennedy’s theorem = Instantaneous centres in linkages
‘D’ Alembert’s principle = Dynamic forces in linkages
Grubler’s rule = Mobility of linkages
In Parson’s turbine if a is nozzle angle, then the maximum efficiency of turbine in:
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Solution
Maximum efficiency of turbine \((\eta _{max})=\frac{2cos^{2}\alpha }{(1+cos^{2})\alpha }\)
For the same maximum pressure, and heat input, the most efficient cycle in:
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Solution
For the same maximum pressure and heat input, otto cycle is most efficient cycle. It is the thermodynamic cycle which is most commonly used in automobile engines.
The equation of a velocity distribution over a plate is given as u = 2y – y2 where, u= velocity in m/s at apoint y m from the plate perpendicularly. If μ= 8.6 poise, then the shress stress at a point 15 cm from the boundary will be ________.
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Solution
The values of enthalpy of starting of compression,at end of compression and at the end of condensation are 85 KJ/kg,185 KJ/kg and 210 kJ/kg respectively. Then the value of COP of vapour compression refrigeration system will be________.
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Solution