A load weighing 80 kg was lifted by means of a lever by 25 cm, applying a force of 400 N to the long arm of the lever.

| July 22, 2021 | education

A load weighing 80 kg was lifted by means of a lever by 25 cm, applying a force of 400 N to the long arm of the lever. Determine the efficiency of the lever if the point of application of the force dropped by 60 cm.

m = 80 kg.

g = 10 m / s2.

h1 = 25 cm = 0.25 m.

F2 = 400 N.

h2 = 60 cm = 0.6 m.

Efficiency -?

The efficiency coefficient shows what part of the spent work Az, expressed as a percentage, goes into useful work Ap: Efficiency = Ap * 100% / Az.

Useful work when lifting a body using the lever Ap is expressed by the formula: Ap = m * g * h1, where m is the mass of the load, g is the acceleration of gravity, h1 is the height of the load.

The expended work Az will be expressed by the formula: Az = F2 * h2, the force applied to the lever, h2 is the distance the lever has dropped.

The formula for efficiency will take the form: efficiency = m * g * h1 * 100% / F2 * h2.

Efficiency = 80 kg * 10 m / s2 * 0.25 m * 100% / 400 N * 0.6 m = 83%.

Answer: the lever has an efficiency of 83%.



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