A diesel tractor consumes 5 litres per hour of fuel whose density is 0.836 kg per litre. The heating value of the fuel is 45.4 MJkg^-1. If the thermal efficiency of the engine is 0.30, the transmission efficiency is 0.90 and the tractive efficiency is 0.75, the drawbar power of the tractor will be __________
a) 10.54 KW
b) 13.18 KW
c) 18.98 KW
d) 39.53 KW

Answer: a
Explanation: Thermal efficiency, η = \(\frac{Brake\, power}{Fuel\, consumption*Density}\)*100
BP = \(\frac{FC*CV*\eta}{100} \)
BP = \(\frac{5*10^{-3}*0.836}{3600}*\frac{45.4*10^6*30}{100} \)
BP = 15.814 KW
DP of the tractor = 15.814*0.90*0.75
= 10.67KW.