Question

the diagram shows a swinging pendulum. which best explains what happens to the motion of the pendulum due to the law of conservation of energy? \bigcirc the pendulum will slow down and eventually stop moving as the mechanical energy transforms to thermal energy. \bigcirc the pendulum will slow down and eventually stop moving as the mechanical energy disappears. \bigcirc the pendulum will continue moving at the same speed because mechanical energy is created as the pendulum moves. \bigcirc the pendulum will slow down but will not stop moving because some of the mechanical energy is destroyed.

Explanation:

1. Recall the law of conservation of energy: Energy cannot be created or destroyed, only transformed.
2. Analyze each option:

• Option 1: In a real pendulum, there's air resistance and friction at the pivot. Mechanical energy (kinetic + potential) is transformed into thermal energy (due to friction/resistance), causing the pendulum to slow down and eventually stop. This matches the law (energy transforms, not disappears).
• Option 2: Energy doesn't disappear, so this is wrong.
• Option 3: Mechanical energy isn't created; it's transformed, and energy loss (due to non - conservative forces like friction) occurs, so speed can't stay same. Wrong.
• Option 4: Energy isn't destroyed, and in reality, with energy loss to thermal, it will stop eventually. Wrong.

Answer:

The pendulum will slow down and eventually stop moving as the mechanical energy transforms to thermal energy. (The first option in the list of choices)