Waec Model Questions Vol1 2023 Agricultural Science Question 3

A farmer wishes to clear a 0.5‑hectare plot of weeds using three hand tools: a hoe, a cutlass and a garden fork. Under identical field conditions he records the following data for each tool: - Time taken to clear the 0.5 ha: Hoe – 4.5 h, Cutlass – 3.2 h, Fork – 5.0 h. - Average force applied per stroke: Hoe – 30 N, Cutlass – 45 N, Fork – 25 N. - Stroke length: Hoe – 0.40 m, Cutlass – 0.60 m, Fork – 0.35 m. - Strokes made per minute: 150 strokes/min for each tool. Using this information, answer the following: a) Calculate the total mechanical work (in kilojoules) performed by each tool in one hour of operation. b) Determine which tool is the most energy‑efficient for clearing the field, expressed as work (kJ) required per square metre cleared. c) Based on the efficiency results and the ergonomics of the forces involved, recommend the most suitable tool for the farmer and justify your choice.