Machine Design
A screw will be self locking, if

Friction angle is more than helix angle
Friction angle is less than helix angle
Efficiency of screw is 100%
Friction angle is equal to helix angle

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
For unequal width of butt straps, the thicknesses of butt straps are

0.75 t for wide strap on the inside and 0.625 t for narrow strap on the outside
0.75 t for both the straps on the inside and outside
0.75 t for narrow strap on the inside and 0.625 t for wide strap on the outside
0.625 t for both the straps on the inside and outside

ANSWER DOWNLOAD EXAMIANS APP