Waec Model Questions Vol1 2023 Agricultural Science Question 4

A small diesel‑powered tractor is used for ploughing. The engine is rated at 15 kW at 2000 rpm and consumes 3.5 L of diesel per hour at full load. The tractor pulls a single‑blade plough whose draft force varies linearly from 1200 N at the start of a furrow to 1800 N at the end of the furrow. Each furrow is 30 m long and the operator records a travel time of 2.5 minutes per furrow. Answer the following: a) Determine the average mechanical power (in kW) required to pull the plough over one furrow. b) Calculate the percentage of the engine’s rated power that is actually utilized during ploughing. c) Using the fuel consumption data, compute the specific fuel consumption (SFC) in kg kW⁻¹ h⁻¹, assuming diesel density of 0.85 kg L⁻¹. d) Identify two probable sources of inefficiency in the tractor‑plough system and suggest practical measures to improve overall performance.