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WAEC Physics 2025 Objective — Question 2

Question 2 of 51 from the West African Examinations Council (WAEC) Physics 2025 Objective paper, with the correct answer and a full explanation.

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The diagram below illustrates a pulley system used to raise a 10kg load. If the effort F needed to raise the load is 70N, calculate the efficiency of the machine [g = 10 ms⁻²]

Diagram for question 2Diagram for question 2
  • A. 20.0%
  • B. 35.7%Correct
  • C. 50.0%
  • D. 75.0%

Explanation

MA = Load/Effort = (10×10)/70 = 10/7. VR = number of pulleys/strings = 4. Efficiency = MA/VR × 100 = (10/7)/4 × 100 = 35.71%.

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