Question

A pair of bullocks exert 100 kg pull at 30° to the horizontal while making a V-shape furrow 15 cm wide and 5 cm deep. The speed of ploughing is 3 KMPH. What is the unit draft on the implement and horsepower developed by the bullocks?

(a) 2.31 kg/cm^2; 0.96 HP

(b) 2.11 kg/cm^2; 0.86 HP

(c) 2.56 kg/cm^2; 0.98 HP

(d) 3.11 kg/cm^2; 0.76 HP

This question was posed to me during an online exam.

The above asked question is from Tillage in section Tillage, Disc Plough & Numericals of Farm Machinery

Answer 1

The correct answer is (a) 2.31 kg/cm^2; 0.96 HP

Best explanation: Cross sectional area = \(\frac{1}{2}\)*b*h = \(\frac{1}{2}*15*5\) = 37.5cm^2

Unit draft (Du) = \(\frac{P cosθ}{A} = \frac{100*cos30°}{37.5}\) = 2.31kg/cm^2

Power = \(\frac{[Draft (kg)*S (\frac{m}{s})]}{75}\) hp = \(\frac{[P cos30°*3*1000]}{75*60*60}\)=0.96 HP.