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184_notes:examples:week3_particle_in_field [2018/05/24 15:02] – [Solution] curdemma | 184_notes:examples:week3_particle_in_field [2021/05/19 15:01] (current) – schram45 |
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===Representations=== | ===Representations=== |
[{{ 184_notes:3_particle_acceleration_field.png?200 |Particle in the Electric Field}}] | [{{ 184_notes:3_particle_acceleration_field.png?200 |Particle Q in the Electric Field}}] |
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| <WRAP TIP> |
| ===Assumption=== |
| No gravitational effects are being considered in this problem. Typically point charges are really small and have negligible masses. This means that the gravitational force would be very small compared to the electric force acting on the particle in the accelerator and can be excluded from the calculations and representation. |
| </WRAP> |
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===Goal=== | ===Goal=== |
&= -QE_0L | &= -QE_0L |
\end{align*} | \end{align*} |
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| <WRAP TIP> |
| ===Assumption=== |
| Assuming the electric field is constant within the accelerator allows the E0 to be taken out of the integral in this problem. |
| </WRAP> |
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The physical significance of this result is that the particle "loses" QE0L of electric potential energy as it travels through the electric field. We do not transfer any energy to the surroundings (through heat, friction, etc.), so this "lost" potential energy must have just been converted to kinetic energy. 0=ΔEsys=ΔU+ΔK=−QE0L+12m(v2f−v2i)
| The physical significance of this result is that the particle "loses" QE0L of electric potential energy as it travels through the electric field. We do not transfer any energy to the surroundings (through heat, friction, etc.), so this "lost" potential energy must have just been converted to kinetic energy. 0=ΔEsys=ΔU+ΔK=−QE0L+12m(v2f−v2i)
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| <WRAP TIP> |
| ===Assumption=== |
| Assuming there is a conservation of energy allows the total change in energy of the system to be zero. |
| </WRAP> |
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Remember that →vi=0, so we can solve for the unknown →vf: | Remember that →vi=0, so we can solve for the unknown →vf: |
\begin{align*} | \begin{align*} |