How Do You Calculate the Acceleration of an Electron in Motion?

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Homework Help Overview

The problem involves calculating the acceleration of an electron that starts from rest and moves with constant acceleration over a specified distance and time. The context is kinematics, specifically dealing with motion equations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the application of kinematic equations, particularly focusing on the initial conditions of the motion. Questions arise regarding the initial position and how it affects the calculation of acceleration.

Discussion Status

Some participants have provided guidance on interpreting the problem statement and the implications of starting from rest. There is an acknowledgment of the need to clarify the initial position, with suggestions to consider different values for it. The discussion reflects varying interpretations of the initial conditions.

Contextual Notes

Participants note the conversion of units from centimeters to kilometers and milliseconds to seconds, as well as the implications of choosing an initial position for the calculations. The original poster expresses uncertainty about how to proceed with the calculations given the initial conditions.

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Homework Statement


electron starting from rest and moving with constant acceleration travels 4.7cm in 8.2ms. What is the magnitude of this acceleration? Answer in km/s^2

Homework Equations


X=Xi + (Vi)t + 1/2at^2

The Attempt at a Solution


Vi = 0 so the equation becomes X = Xi + 1/2at^2
t = 8.2ms and X = 4.7 so 4.7 = Xi + 1/2a(8.2)^2

I feel like I did everything right up to this point but all I need is acceleration to plug in but I'm not sure how to get that.
 
Last edited:
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You do not need to plug in acceleration. You are trying to solve for a.

Thus, what you need to plug in is xi, the starting position of the particle.
 
4.7cm = .000007km and 8.2ms = .0082 seconds

electron is from rest so Vi=0 so the equation is 2(X-Xi)/t^2, I have time and I have X which equals .000047km. How to I find Xi, or is that also zero?
 
Last edited:
Hello!
problem statement says that: "starting from rest", which means that initial velocity is zero. For initial position Xi you can chose whichever value you like. What is given - the distance moved, that is X-Xi. You can chose X = 4.7 cm only if your Xi = 0.
 
thanks guys, yeah I got it, it was 1.398 km/s^2
 
your welcome
 

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