question_answer

Consider the following statements regarding power screws:                                    

1. The efficiency of a self-locking screw cannot be more than 50%

2. If the friction angle is less than the helix angle of the screw, then the efficiency will be more than 50%

3. The efficiency of ACME (trapezoidal) thread is less than that of square thread.

Of these statements:                            

A) 1, 2 and 3-are correct     

B) 2 and 3 are correct 

C) 1 and 3 are correct                     

D) 1 and 2 are correct