Question

1000 joules of energy are put into a pulley system, and 400 joules come out. what does the law of conservation of energy imply about the lost energy? (1 point)
the lost energy is caused by friction.
the pulley system could be improved to conserve some of the lost energy.
the lost energy cannot be recovered.
the lost energy is not truly lost, but it changed into a different form.

Explanation:

The Law of Conservation of Energy states that energy cannot be created or destroyed, only transformed. In this pulley system, the "lost" energy (1000 - 400 = 600 joules) must have been converted into another form (such as heat due to friction). The first option only gives a cause (friction) but doesn't address the core of the conservation law. The second option is about improvement (not directly related to the law's implication). The third option contradicts the law (energy isn't truly lost). The fourth option aligns with the law as it emphasizes energy transformation.

Answer:

The lost energy is not truly lost, but it changed into a different form.