A team of students builds a lever as a science project. They expand 10,300 joules of energy to lift some bricks with the lever. If 6,283 joules of energy are applied to the bricks what is the levers efficiency?
Efficiency = (Output/Input) x 100%
The input in this case is the energy applied to the bricks, which is 6,283 joules. The output is the energy expanded by the lever to lift the bricks, which is 10,300 joules.
Efficiency = (10,300/6,283) x 100%
Efficiency = 164%
This calculation shows an efficiency greater than 100%. This is not possible as it violates the law of conservation of energy, which states that the total energy input into a system must equal the total energy output.
Therefore, there may be an error in the input or output measurements, or the lever may not have been calibrated or used properly. Without further information, the efficiency cannot be accurately determined.
To find the lever's efficiency, we'll use the formula:
Efficiency = (Useful energy output / Total energy input) * 100%
Given that the total energy input is 10,300 joules and the useful energy output is 6,283 joules, we can substitute these values into the formula:
Efficiency = (6283 / 10300) * 100%
Efficiency = 0.609 * 100%
Efficiency = 60.9%
Therefore, the lever's efficiency is 60.9%.