Subtopic: Selection, operation, maintenance and repair of I.C. engines
Question Statement:
A power tiller rotary unit has a rotor width of $60\text{ cm}$ and operates at a forward speed of $1.8\text{ km/h}$ ($0.5\text{ m/s}$) to a depth of $10\text{ cm}$. If the rotary tiller requires a specific work of $120\text{ kJ/m}^3$ of soil cut, calculate the net rotary shaft power required in $\text{kW}$ (round off to 2 decimal places).
Answer Key:
3.6
Step-by-Step Solution & Explanation
Volume rate of soil cut:
$\dot{V} = w \times d \times v = 0.60\text{ m} \times 0.10\text{ m} \times 0.5\text{ m/s} = 0.030\text{ m}^3/\text{s}$
Net power required:
$P = \text{Specific work} \times \dot{V} = 120\text{ kJ/m}^3 \times 0.030\text{ m}^3/\text{s} = 3.60\text{ kW}$