In a metro station, it was observed that on an average 20 people per minute were using the escalator to reach at a height of 15 metres. Calculate the power of the escalator assuming the average mass of people to be 50 kg and acceleration due to gravity to be 10 m/s2.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 2.5 kW.
In this case, 20 people use the escalator every minute, each with an average mass of 50 kg. This means the total mass lifted per minute is 1000 kg. They are raised to a height of 15 metres against gravity, requiring energy. The total work done per minute is mass multiplied by height and gravity. Dividing this energy by time gives power. On calculation, the escalator’s power comes out to be 2500 watts (2.5 kW) approximately.