Physical Science B Semester Exam

Question

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Question
A team of students builds a lever as a science project. They expend 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 lever’s efficiency?(1 point)
Responses

61%
61%

164%
164%

39%
39%

0.61%

Answer 1

To calculate the efficiency of the lever, you can use the formula for efficiency:

\[ \text{Efficiency} = \left( \frac{\text{Useful Output Energy}}{\text{Input Energy}} \right) \times 100 \]

In this case, the useful output energy is the energy applied to the bricks (6,283 Joules), and the input energy is the energy expended by the students (10,300 Joules).

Substituting the values into the formula:

\[ \text{Efficiency} = \left( \frac{6,283 \text{ J}}{10,300 \text{ J}} \right) \times 100 \]

Calculating this gives:

\[ \text{Efficiency} = \left( 0.6100 \right) \times 100 = 61% \]

Therefore, the lever’s efficiency is 61%.