Understanding Efficiency
Efficiency is the ratio of useful output work to the total input work. In this case:
* Useful output work: The work done in lifting the crate (230 J).
* Total input work: The work required by the device (420 J).
Calculation
1. Formula: Efficiency = (Useful Output Work / Total Input Work) * 100%
2. Plug in the values: Efficiency = (230 J / 420 J) * 100%
3. Calculate: Efficiency ≈ 54.76%
Answer: The efficiency of the mechanical device is approximately 54.76%.
