Choose The Best Answer For The Multiple-Choice Questions From (A) To (G) And (M) To (9). (Warning: There Is A Penalty Of 1 Right Answer For Every 3 Wrong Answers.) If Your Answer Is Not Listed For A Multiple-Choice Question, Then Put Your Own Answer Next To The Question. Solve The Problems At (H) And (R). Always Show Your Work. A Single-Thread Square Power

 

Choose the best answer for the multiple-choice questions from (a) to (g) and (m) to (q). (Warning: There is a penalty of 1 right answer for every 3 wrong answers.) If your answer is not listed for a multiple-choice question, then put your own answer next to the question. Solve the problems at (h) and (r). Always show your work. A single-thread square power screw has a major diameter of 28 mm and a pitch of 4 mm. The diameter of the collar is assumed as d=36 mm and the coefficients of friction both for the threads and collar are taken as f=f=0.05. The load acting on the screw is F = 5 kN. (a) How much is the torque for raising the load, Tx (in N-m)? [4 Marks] i) 6.45 ii) 10.95 iii) 0.07 iv) 4.57 ii) 0.07 (b) How much is the torque for lowering the load, T (in N-m)? i) 4.57 iii) 6.45 iv) 10.95 (c) Is the screw self-locking and why? i) Yes, because T>0 ii) No, because T>0 iii) Yes, because T