Question

During a washing cycle, a washing machine uses 3301w usefully. The machine also radiates 159w of sound, and 397w more is wasted as heat. Calculate the efficiency of the washing machine. Give your answer as a percentage and round it to 2 decimal places.

Answer 1

The efficiency of the washing machine is calculated by dividing the useful energy output (3301W) by the total energy input (3857W) and then multiplying by 100, resulting in an efficiency of approximately 85.61%.

Step-by-step explanation:

To calculate the efficiency of a washing machine, one must compare the useful energy output to the total energy input. The machine uses 3301 watts usefully, while 159 watts are lost as sound and an additional 397 watts are wasted as heat. Therefore, the efficiency can be calculated using the formula:

Efficiency (%) = (Useful Energy Output / Total Energy Input) × 100

Total Energy Input = Useful Energy + Energy lost as sound + Energy lost as heat

Total Energy Input = 3301W + 159W + 397W = 3857W

Efficiency (%) = (3301W / 3857W) × 100

Efficiency (%) = (3301 / 3857) × 100

Efficiency (%) ≈ 85.61%

Thus, the efficiency of the washing machine is approximately 85.61% when rounded to two decimal places.