Theory Of Machine - Practice Test

[#251] The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where μ = Coefficient of friction, W = Load over the bearing, R = Radius of bearing)

(A) μWR

(B) $$frac{3}{4}$$μWR

(C) $$frac{2}{3}$$μWR

(D) $$frac{1}{2}$$μWR

Correct Answer

(D) $$frac{1}{2}$$μWR

[#252] In a four bar chain or quadric cycle chain

(A) Each of the four pairs is a turning pair

(B) One is a turning pair and three are sliding pairs

(C) Two are turning pairs and two are sliding pairs

(D) Three are turning pairs and one is a sliding pair

Correct Answer

(A) Each of the four pairs is a turning pair

[#253] The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

(A) To dip the nose and tail

(B) To raise the nose and tail

(C) To raise the nose and dip the tail

(D) To dip the nose and raise the tail

Correct Answer

(C) To raise the nose and dip the tail

[#254] A torsional system with discs of moment of inertia $${I_1}$$ and $${I_2}$$ as shown in the below figure, is gear driven such that the ratio of speed of shaft B to shaft A is 'G'. Neglecting the inertia of gears, the equivalent inertia of disc on shaft B at the speed of shaft A is equal to

(A) $${ ext{G}} imes {I_2}$$

(B) $${{ ext{G}}^2} imes {I_2}$$

(C) $$frac{{{I_2}}}{{ ext{G}}}$$

(D) $$frac{{{I_2}}}{{{{ ext{G}}^2}}}$$

Correct Answer

(B) $${{ ext{G}}^2} imes {I_2}$$

Explanation

Solution:

[#255] A body having moment of inertia of 30 kg m 2 is rotating at 210 RPM and mashes with another body at rest having M.I. of 40 kg m 2 . The resultant speed after meshing will be

(A) 90 RPM

(B) 100 RPM

(C) 80 RPM

(D) None of the mentioned

Correct Answer

(A) 90 RPM

Theory Of Machine - Study Mode

[#251] The frictional torque transmitted in a flat pivot bearing, assuming uniform wear, is (Where μ = Coefficient of friction, W = Load over the bearing, R = Radius of bearing)

Correct Answer

[#252] In a four bar chain or quadric cycle chain

Correct Answer

[#253] The engine of an aeroplane rotates in clockwise direction when seen from the tail end and the aeroplane takes a turn to the left. The effect of gyroscopic couple on the aeroplane will be

Correct Answer

[#254] A torsional system with discs of moment of inertia $${I_1}$$ and $${I_2}$$ as shown in the below figure, is gear driven such that the ratio of speed of shaft B to shaft A is 'G'. Neglecting the inertia of gears, the equivalent inertia of disc on shaft B at the speed of shaft A is equal to

Correct Answer

Explanation

[#255] A body having moment of inertia of 30 kg m 2 is rotating at 210 RPM and mashes with another body at rest having M.I. of 40 kg m 2 . The resultant speed after meshing will be

Correct Answer