The figure gives a plot of potential energy versus position along an x axis. We – [Free] B52
The figure gives a plot of potential energy versus position along an x axis. We release a particle at x=4.0m with a kinetic energy of 2.0 J. Which of the following best describes the particle’s motion? A.) It can escape to the well at the right and will then move back and forth between the two wells B.) It can escape from the plot off to the left side of the plot C.) It is trapped in the well at the left D.) It can escape from the plot off to the left side and also to the right side E.) It can escape to the well at the right but will be trapped there (option was incorrect)
Answer
๐ Potential Energy vs Position: Particle Motion Analysis
๐ง Concept Recap
- Potential Energy (U): Energy stored due to position in a field.
- Can be positive or negative depending on the system.
- The graph shows energy wells โ valleys where energy is lower than nearby regions.
โ๏ธ Energy Types
- Kinetic Energy (K): Energy due to motion.
- Total Energy (E): Sum of kinetic and potential energy.
๐ Interpreting the Graph
If Total Energy > Potential Energy, particle can move freely in that region.
If Total Energy < Potential Energy, particle cannot enter that region.
๐ Given Values
Potential Energy (U) = 3.0 J at x = 4.0 m
โ Total Energy (E) = K + U = 2.0 + 3.0 = 5.0 J
๐ Motion Inference
- To the left of x = 3.0 m, U > 5.0 J โ Cannot move left.
- To the right, U reaches 5.0 J โ Particle is also blocked.
- Hence, particle is confined in the well to the left of the graph.
Only when total energy exceeds barrier potential can the particle escape a well โ which is not the case here.