The co-efficient of rolling resistance for a motor vehicle weighing 6000kgf is 0.019 and the co-efficient of air resistance is 0.0030 in the formula R KW + KAV2 kgf, where A is the m² of the frontal area and V is the speed in km/hr. The transmission efficiency in top gear 6.2:1 is 88% and that in the second gear of 15:1 is 80%. The frontal area is 5.2m². If the vehicle has to have a maximum speed of 90km/hr. in top gear; calculate, i) The engine b.h.p required, ii) The engine speed, if the driving wheels have an effective diameter of 81 cm. iii) The maximum grade the vehicle can negotiate at the above engine speed in second gear. Where, W = the total weight of the vehicle, K = Constant of rolling resistance = 0.015 and Ka=co-efficient of air resistance, kgf-hr/m²-km² = 0.0040.