In detail describe and discuss gearless traction elevators

There are two pairs of closed soft tooth surface spur gears A and B,Parameters of A: modulus m = 2mm, number of teeth Z1 = 40, Z2 = 90 , width of teeth b = 60mm.Parameters of B : modulus m = 4mm, number of teeth Z1 = 20, Z2 = 45 , width of teeth b = 60mm.The accuracy of the two pairs of gears is grade8, and other conditions are the same. Try to compare the contact fatigue strength and bending fatigue strength of the two pairs of gears? And explain the reason.

A mini motorcycle is driven by a combustion engine with mechanical transmission. The 12Hp motor spins at a speed of 1150 rpm. The motorcycle runs at a linear speed of 45 km/h on 12-inch wheels. Preliminary center to center distance is 13”. This type of motorcycle requires two strands (conical double sleeve assembly) and is subjected to hard shocks. Can I get a detailed explanation for Choice of chain and sprocket. (Standard part number, see catalog) https://pdf.directindustry.com/pdf/martin-sprocket-gear/general-catalog/9091-246439.html

A 2:1 speed reduction drive (Fig Q4) between two parallel shafts at 1200 mm centre distance is being provided by a V-belt of mass 0.5 kg/m. The diameter of the driving pulley is 200 mm and the driving shaft rotates at 900 rev/min. The driven pulley is 400 mm diameter. The angle of the pulley grooves is 40°, and the coefficient of friction between belt and pulleys is 0.35. If the maximum beit tension is 400 N determine: (i) The linear belt speed and the centripetal tension due to that belt speed. (ii) The angle of lap on each pulley (iii) The maximum power that may be transmitted Ø200 1200 Ø400