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Q4. A single-start worm rotates a 50-tooth worm-wheel in a simple lifting machine. The system is driven by an effort wheel that is 250 mm in diameter.

(a) If the effort required lifting a mass of 700 kg is 125 N with an overall efficiency of 35%, calculate EACH of the following.

(i) the mechanical advantage of the lifting machine. (2)

(ii) the velocity ratio of the lifting machine. (2)

(iii) the diameter of the load wheel. (4)

(iv) the time taken to raise the load 1. 5 m if the effort wheel rotates at a constant speed of 50 rpm. (4)

(b) Sketch the arrangement. (4)