Which of the following statement is correct regarding power screws?
A. The efficiency of a self locking screw can not be more than 50%
B. The efficiency of Acme (trapezoidal) thread is less than that of a square thread
C. If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%
D. Both (A) and (B)
Answer: Option D
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A cotter joint is used to connect two __________ rods.
A. Co-axial
B. Perpendicular
C. Parallel
D. None of these
The rated life of a bearing varies
A. Directly as load
B. Inversely as square of load
C. Inversely as cube of load
D. Inversely as fourth power of load
The bending stress in a curved beam is
A. Zero at the centroidal axis
B. Zero at the point other than centroidal axis
C. Maximum at the neutral axis
D. None of these
The centre to centre distance between two consecutive rivets in a row, is called
A. Margin
B. Pitch
C. Back pitch
D. Diagonal pitch
Options B and C correct
The efficiency of self locking screws is less than 50%
If friction angle is less than helix angle, then the screw will be Overhauling & efficiency of overhauling screw is more than 50%..so all options are correct