A load of 120 kg is lifted with a movable block applying a force of 750N to the free end of the rope

| July 18, 2021 | education

A load of 120 kg is lifted with a movable block applying a force of 750N to the free end of the rope. What is the unit efficiency?

m = 120 kg.

g = 10 m / s2.

F = 750 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 will be expressed by the formula: Az = F * L, where L is the length of the rope that was pulled.

For the movable block L = 2 * h.

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

Efficiency = 120 kg * 10 m / s2 * 100% / 2 * 750 N = 80%.

Answer: the mobile unit has an efficiency of 80%.



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