Question

Электроподъемник, мощность которого 500 Вт, поднимает груз массой 50 кг на высоту 5 м за 20 секунд. КПД такого электроподъёмника составляет (в %) ...

Answer 1

Кпд=m*g*h/N*t=50*10*5/500*20=0,25=25%

Answer 2

Calculation of Efficiency (КПД) of the Electric Hoist

To calculate the efficiency (КПД) of the electric hoist, we need to know the input power, output power, and the formula for efficiency. The formula for efficiency is:

Efficiency (КПД) = (Output Power / Input Power) * 100%

Given information: - Input power (мощность) of the electric hoist: 500 Вт (watts) - Mass (масса) of the load: 50 кг (kilograms) - Height (высота) lifted: 5 м (meters) - Time taken to lift the load: 20 сек (seconds)

To calculate the output power, we can use the formula:

Output Power = Work Done / Time

The work done is equal to the force applied multiplied by the distance moved. In this case, the force applied is equal to the weight of the load, which is given by:

Force = Mass * Gravity

Where gravity is approximately 9.8 m/s^2.

Let's calculate the efficiency step by step:

1. Calculate the force applied: - Mass of the load: 50 кг - Gravity: 9.8 m/s^2 - Force = 50 кг * 9.8 m/s^2

2. Calculate the work done: - Distance moved: 5 м - Work Done = Force * Distance

3. Calculate the output power: - Time taken: 20 сек - Output Power = Work Done / Time

4. Calculate the efficiency: - Efficiency (КПД) = (Output Power / Input Power) * 100%

Let's calculate the values:

1. Calculate the force applied: - Mass of the load: 50 кг - Gravity: 9.8 m/s^2 - Force = 50 кг * 9.8 m/s^2 = 490 Н (Newtons) 2. Calculate the work done: - Distance moved: 5 м - Work Done = Force * Distance = 490 Н * 5 м = 2450 Дж (Joules) 3. Calculate the output power: - Time taken: 20 сек - Output Power = Work Done / Time = 2450 Дж / 20 сек = 122.5 Вт (watts) 4. Calculate the efficiency: - Input power of the electric hoist: 500 Вт - Efficiency (КПД) = (Output Power / Input Power) * 100% = (122.5 Вт / 500 Вт) * 100% = 24.5% (rounded to one decimal place)

Therefore, the efficiency (КПД) of the electric hoist is approximately 24.5%.

Please note that the above calculations are based on the given information and assumptions.