Calculate the size of tractor to pull a four bottom 35 cm MB plough through a depth of 10 cm. the soil resistance is 0.5 kg/cm². The speed of the tractor is 5.5 km/h, the transmission and tractive efficiency of the tractor being 85% and 30% respectively.
a) 41.1 KW
b) 43.9 KW
c) 42.7 KW
d) 44.8 KW

Answer: a
Explanation: Furrow cross section = 4*35*10=1400 cm²
Total draft = 1400 * 0.5 kg = 700 kg
700 * 9.8 = 6860 N
Power = 6860 * \(\frac{(5.5*1000)}{(60*60)}*\frac{1}{0.85}*\frac{1}{0.30}\)N.m/s = 41100.21 W
= 41.1 KW.