Theory of Machine The efficiency of a screw jack is maximum, when (where α = Helix angle, and φ = Angle of friction) α = 90° - φ α = 45° - φ/2 α = 90° + φ α = 45° + φ/2 α = 90° - φ α = 45° - φ/2 α = 90° + φ α = 45° + φ/2 ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine When the two elements of a pair have __________ when in motion, it is said to a lower pair. None of these Line or point contact Body contact Surface contact None of these Line or point contact Body contact Surface contact ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine Which one of the following is an exact straight line mechanism using lower pairs? Peaucellier’s mechanism Robert’s mechanism Watt’s mechanism Grasshopper mechanism Peaucellier’s mechanism Robert’s mechanism Watt’s mechanism Grasshopper mechanism ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine In a four-bar chain it is required to give an oscillatory motion to the follower for a continuous rotation of the crank. For the lengths of 50 mm of crank and 70 mm of the follower, determine theoretical maximum length of coupler. The minimum length of the coupler will be 45 mm Slightly more than 45 mm Slightly less than 45 mm 95 mm 45 mm Slightly more than 45 mm Slightly less than 45 mm 95 mm ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine In vibration isolation system, if ω/ωn > 1, then the phase difference between the transmitted force and the disturbing force is 270° 180° 0° 90° 270° 180° 0° 90° ANSWER DOWNLOAD EXAMIANS APP
Theory of Machine Two heavy rotating masses are connected by shafts of lengths l₁, l₂ and l₃ and the corresponding diameters are d₁, d₂ and d₃. This system is reduced to a torsionally equivalent system having uniform diameter d = d₁ of the shaft. The equivalent length of the shaft is (l₁ + l₂ + l₃)/3 l₁ + l₂ + l₃ l = l₁ + l₂.(d₁/d₂)³ + l₂.(d₁/d₃)³ l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴ (l₁ + l₂ + l₃)/3 l₁ + l₂ + l₃ l = l₁ + l₂.(d₁/d₂)³ + l₂.(d₁/d₃)³ l = l₁ + l₂.(d₁/d₂)⁴ + l₃.(d₁/d₃)⁴ ANSWER DOWNLOAD EXAMIANS APP
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