A wheel of a car is made up of two parts (1)the central metal rim, and (2)the rubber tyre. The width of the tyre W = 16.5 cm and height h = 10.7 cm. The rim overlaps the tyre. The total weight of the car is 1500 kg distributed evenly. The tyres are inflated with air to a pressure 2.0 kg/cm2. The density of air at pressure of 1.0 kg/cm2 and at room temperature equals 1.29 g/litre. The outer diameter of the tyre is 55.4 cm and that of the rim is 40 cm.