Question

При подъеме рычагом мешка с песком массой 65 кг на три среди метра производится работа 20 Дж . Каков КПД рычага ?

Answer 1

1) A = Fs = mgs = 65 · 10 · 3 = 1950 ДЖ
2) КПД = Апол/Азатр = 1950 : 20 = 97,5 ⇒ 975%

Answer 2

Calculating the Efficiency of the Lever

To calculate the efficiency of the lever, we can use the formula:

Efficiency (η) = (Useful work output / Total work input) x 100%

Given: - Useful work output = 20 J - Total work input = Work done in lifting the sandbag = Force x Distance

The work done in lifting the sandbag can be calculated using the formula: Work = Force x Distance

Calculating Work Done in Lifting the Sandbag

The force applied to lift the sandbag can be calculated using the formula: Force = Mass x Acceleration due to gravity

Given: - Mass of the sandbag (m) = 65 kg - Acceleration due to gravity (g) = 9.81 m/s^2 - Distance lifted (d) = 3 meters

Using the above information, we can calculate the force applied to lift the sandbag and then the work done.

Calculating the Efficiency

Once we have the work done in lifting the sandbag, we can use it to calculate the efficiency of the lever using the formula mentioned earlier.

Let's proceed with the calculations.