A box with nails, the weight of which is 54 kg, is lifted to the fifth floor of a house under construction using

| May 29, 2021 | education

A box with nails, the weight of which is 54 kg, is lifted to the fifth floor of a house under construction using a movable block, acting on a cable with a force of 360 N. Calculate the efficiency of the installation.

m = 54 kg.

g = 10 m / s2.

F = 360 N.

Efficiency -?

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

We will express the useful work Ap by the formula: Ap = m * g * h, where h is the height to which the load was lifted.

The expended work Az is expressed by the formula: Az = F * L, where L is the length of the rope for which they pulled.

For the movable block L = 2 * h.

Efficiency = m * g * h * 100% / F * 2 * h = m * g * 100% / F * 2.

Efficiency = 54 kg * 10 m / s2 * 100% / 2 * 360 N = 75%.

Answer: the installation has an efficiency of 75%.



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