Module 3
1. Module 3
1.47. Page 7
Module 3—Electrical Phenomena
Lesson Summary
At the beginning of this lesson, you were asked the following essential questions:
- How do charged particles move in a uniform electric field? How is this motion similar to a mass moving in a gravitational field?
- Is it possible to predict the velocity, acceleration, and displacement of charged particles moving in electric fields?
Charged particles in uniform electric fields move according to Newton’s laws of motion. This makes the motion of a charged particle very similar to the motion of a mass in a gravitational field. In both cases, the test body accelerates in the direction of an unbalanced force as described by Newton’s second law. If there is no unbalanced force, then the test body maintains its velocity as described by Newton’s first law. If one component of the velocity of a test body is maintaining a constant velocity, while another component is accelerating, then the test body will move through a parabolic trajectory or projectile motion.
The equations used to analyze projectile motion in previous courses can be applied to the motion of a charged particle in a uniform electric field.
For example, the equation Δd =½aΔt2 can be applied not just to projectile motion in a gravitational field, but also to the motion of a charged particle in a uniform electric field. To apply the formula to the motion of a charged particle, you simply take the variable a to refer to the acceleration due to the force of the uniform electric field.
The formula for projectile motion can be used to calculate the velocity, displacement, and acceleration of the motion of charged particles. The engineers who design electrostatic precipitators use the formulas of projectile motion to ensure that these devices work to effectively remove over 99% of the particulate matter from the flue gases produced at coal-fired generating stations.