Understanding Efficiency
Efficiency is the ratio of useful work output to the total work input. It's expressed as a percentage:
Efficiency = (Useful Work Output / Work Input) * 100%
Applying the Information
* Work Input: 420 J (the energy put into the device)
* Useful Work Output: 230 J (the energy used to lift the crate)
Calculation
Efficiency = (230 J / 420 J) * 100%
Efficiency ≈ 54.8%
Answer: The efficiency of the mechanical device is approximately 54.8%.
