Using a lever, the efficiency of which is 75%, lift a load weighing 150 kg to a height of 50 cm.

Using a lever, the efficiency of which is 75%, lift a load weighing 150 kg to a height of 50 cm. Determine how far the long arm of the lever sank if a force of 500 N was applied to it.

Efficiency = 75%.

m = 150 kg.

g = 10 m / s2.

F1 = 500 N.

h = 50 cm = 0.5 m.

h1 -?

Efficiency -?

The efficiency of the lever efficiency 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 An is expressed by the formula: An = m * g * h, where m is the mass of the load, g is the acceleration of gravity, h is the height to which the load was lifted.

The expended work Az will be expressed by the formula: Az = F1 * h1, where F1 is the force that acts from the opposite side of the lever, h1 is the distance the lever has dropped.

The formula for determining the efficiency of the lever will take the form: efficiency = m * g * h * 100% / F1 * h1.

h1 = m * g * h * 100% / F1 * efficiency.

h1 = 150 kg * 10 m / s2 * 0.5 m * 100% / 500 N * 75% = 2 m.

Answer: when lifting the load, the long arm of the lever dropped by h1 = 2 m.