Question

mple lever. A lift is used to carry boxes to the top floor of a hotel 20 m high. A total weight of 100 kg of boxes was carried up in 20 seconds. If the useful output of the engine driving the lift mechanism is 1.2 kilowatt, calculate the efficiency of the engine of the lift mechanism. (a) (i) What is meant by a​

Answer 1

The efficiency of the engine of the lift mechanism can be determined using the formula: Efficiency = (useful output power / input power) * 100%. The input power can be calculated using the formula: Input power = work done / time. Therefore, the efficiency of the engine of the lift mechanism is approximately 122.45%.

Step-by-step explanation:

The efficiency of the engine of the lift mechanism can be determined using the formula:

Efficiency = (useful output power / input power) * 100%

First, we need to find the input power. The input power can be calculated using the formula:

Input power = work done / time

In this case, the work done is equal to the weight of the boxes multiplied by the height they were lifted:

Work done = weight * height = 100 kg * 9.8 m/s² * 20 m = 19600 J

Next, we can calculate the input power:

Input power = 19600 J/ 20 s = 980 W

Now, we can use the formula for efficiency:

Efficiency = (1.2 kW / 0.98 kW) * 100% = 122.45%

Therefore, the efficiency of the engine of the lift mechanism is approximately 122.45%.