Multiple choice questions (MCQ) on Theory of machines
21. The couple will balance one another couple when they are in the same plane and
a. Have unequal moments and their direction of rotation is opposite
b. Have equal moments and their direction of rotation is same
c. Have equal moments and their direction of rotation is opposite
d. None of the above
22. The frictional torque transmitted in a conical pivot bearing, considering uniform pressure is (Where R is the radius of shaft, α is semi angle of the cone, μ is coefficient of friction, and W is the load on bearing)
a. (μWR cosecα)/2 b. (3μWR cosecα)/4
c. (2μWRcosecα)/3 d. None of the above
23. The friction circle is a circle drawn when a journal rotates in a bearing. Its radius depends upon the coefficient of friction and
a. Angular velocity of journal b. Magnitude of the forces on journal
c. Radius of journal d. None of the above
24. When the addenda on pinion and wheel is such that the path of approach and path of recess are the half of their maximum possible value, then the length of path of contact is given by (where r is pitch circle radius of pinion, R is the pitch circle radius of wheel and Φ is the pressure angle)
a. {(r2+R2)cosΦ}/2 b. {(r+R)sinΦ}/2
c. {(r+R)cosΦ}/2 d. None of the above
25. The ratio of height of porter governor (when length of arms and links are equal) to the height of watt governor is (Where m is the mass of the ball and M is the mass of sleeve)
a. (m+M)/m b. M/(m+M)
c. m/(m+M) d. None of the above
26. A governor is said to be isochronous when equilibrium speed of all radii of rotation of the balls with in the working range
a. Is constant b. Varies uniformly
c. Is not constant c. None of the above
27. The ratio of tension of two side of a flat belt is given by
a. e-μθ b. eμθ c. e x μ x θ d. None of the above
28. Crowning of a pulley is done to
a. Prevent the slipping of a belt b. To increase the tension of a belt
c. To increase the angle of contact d. None of the above
29. The power transmitted by a belt drive is (T1=Tension on tight side, T2=Tension on slack side, where v = linear velocity, ω = angular velocity)
a. (T1-T2) x v b. (T1-T2) x ω
c. (T1-T2) / v d. (T1-T2) /ω
30. The number of Instantaneous centres in a mechanism is (where n is the number of links)
a. n(n-1)/2 b. 2n(n-1)/3 c. n(2n-1)/2 d. 3n(n-1)/2