The problem in the image involves calculating the average power of an elevator that lifts passengers and its own mass to a certain height. Here is a breakdown:

Given Data:

1. Mass of passengers = $75 \, \text{kg} \times 4 = 300 \, \text{kg}$
2. Mass of the elevator = $400 \, \text{kg}$
3. Total mass = $300 + 400 = 700 \, \text{kg}$
4. Height = $20 \, \text{m}$
5. Time = $2 \, \text{minutes} = 120 \, \text{seconds}$
6. Gravitational acceleration, $g = 9.8 \, \text{m/s}^2$

Step 1: Work Done

The work done $W$ to lift the elevator is: $W = m \cdot g \cdot h$ $W = 700 \, \text{kg} \cdot 9.8 \, \text{m/s}^2 \cdot 20 \, \text{m}$ $W = 137,200 \, \text{J}$

Step 2: Average Power

The average power $P$ is: $P = \frac{W}{t}$ $P = \frac{137,200 \, \text{J}}{120 \, \text{s}}$ $P = 1,143.33 \, \text{W}$

Step 3: Convert to Kilowatts

$P = 1.143 \, \text{kW}$

Final Answer:

The average power of the elevator is approximately 1.143 kW.

Let me know if you want further clarification!

Here are 5 relative questions:

1. How is work related to force and displacement?
2. What is the difference between average and instantaneous power?
3. Why is gravitational acceleration considered constant?
4. What are the units of energy, work, and power?
5. How can efficiency impact power calculations?

Tip: Always convert time to seconds when dealing with power and work equations.