A load weighing 1200 N is lifted using a movable block. For this, a force of 800 N is applied to the free

| September 2, 2021 | education

A load weighing 1200 N is lifted using a movable block. For this, a force of 800 N is applied to the free end of the rope. Determine the efficiency of the movable block.

P = 1200 N.

F = 800 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.

Body weight P is determined by the formula: P = m * g.

Ap = P * h.

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

Efficiency = 1200 N * 100% / 2 * 800 N = 75%.

Answer: the installation has an efficiency of 75%.



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