Find the efficiency of the lever if a body weighing 120 kg is lifted to a height of 12 cm

Find the efficiency of the lever if a body weighing 120 kg is lifted to a height of 12 cm, and the point of application of a force of 360 N has dropped by 50 cm

To find the lever efficiency, we use the formula η = (Ap / Az) ∙ 100%, where useful work Ap = m ∙ g ∙ h, coefficient g = 9.8 N / kg, expended work Az = F ∙ h2, then η = ((m ∙ g ∙ h) / (F ∙ h2)) ∙ 100%. From the condition of the problem it is known that a body with a mass of m = 120 kg is lifted to a height of h1 = 12 cm = 0.12 m, and the point of application of the force F = 360 N dropped to h2 = 50 cm = 0.5 m. Substitute the values of physical quantities in formula and make calculations: η = ((120 ∙ 9.8 ∙ 0.12) / (360 ∙ 0.5)) ∙ 100%, η = 78.4%.
Answer: The lever efficiency is 78.4%.