Subtopic: Sources of power on the farm – human, animal, mechanical, electrical, wind, solar and biomass
Question Statement:
A pair of Haryana bullocks each having a body mass of $450\text{ kg}$ exerts a continuous draft equal to $10\%$ of their combined body weight while pulling an indigenous plough at an average speed of $3.6\text{ km/h}$. Taking $g = 9.81\text{ m/s}^2$, the tractive power developed by the pair of bullocks in $\text{kW}$ is ________ (round off to 2 decimal places).
Answer Key:
0.88
Step-by-Step Solution & Explanation
1. Combined weight of the pair of bullocks ($W$):
$W = 2 \times 450\text{ kg} \times 9.81\text{ m/s}^2 = 8829\text{ N}$
2. Draft force ($P$):
$P = 0.10 \times 8829\text{ N} = 882.9\text{ N}$
3. Forward speed in $\text{m/s}$:
$v = 3.6 \times \frac{5}{18} = 1.0\text{ m/s}$
4. Power output ($P_{out}$):
$P_{out} = P \times v = 882.9\text{ N} \times 1.0\text{ m/s} = 882.9\text{ W} \approx 0.88\text{ kW}$