19. in which position is there all kinetic energy (ke) and no potential energy (pe)?\n1 point\n1\n2\n3\n4\n5\…
19. in which position is there all kinetic energy (ke) and no potential energy (pe)?\n1 point\n1\n2\n3\n4\n5\n20. in which position is ke increasing and pe decreasing?\n1 point\n1\n2\n3\n4\n5\npendulum
Answer
Explanation:
Step1: Recall energy concepts
For a pendulum, potential energy is related to height and kinetic energy to speed. At the lowest - point, height is minimum and speed is maximum.
Step2: Analyze pendulum positions
Position 3 is the lowest point of the pendulum's swing. At this position, the height of the pendulum bob above the lowest - point is zero (minimum), so potential energy $PE = mgh$ (where $h = 0$) is zero, and speed is maximum, so kinetic energy $KE=\frac{1}{2}mv^{2}$ is maximum.
Step3: Analyze energy change
When the pendulum moves from a higher position to a lower position, it is losing height and gaining speed. So, when moving from positions 1 or 5 towards position 3, kinetic energy is increasing and potential energy is decreasing. Position 2 is on the way down from a higher position (like 1) to the lowest position 3, so $KE$ is increasing and $PE$ is decreasing.
Answer:
- 3
- 2