Machine Design
The efficiency of a square threaded screw is maximum if the helix angle is equal to(Where φ = Angle of friction)

45° + φ/2
45° - φ/2
90° - φ
45° - φ

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
Which is correct statement?

A member made of steel will generally be more rigid than a member of equal load carrying ability made of cast iron
A member made of cast iron will generally be more rigid than a member of equal load carrying ability made of steel
Both will be equally rigid
Which one is rigid will depend on several other factors

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
A hollow saddle key is

A taper key which fits half in the key way of hub and half in the key way of shaft
Provided in pairs at right angles and each key is to withstand torsion in one direction only
A taper key which fits in a key way of the hub and is flat on the shaft
A taper key which fits in a key way of the hub and the bottom of the key is shaped to fit the curved surface of the shaft

ANSWER DOWNLOAD EXAMIANS APP