Answers to Your Questions: Q1 & Q2

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The discussion revolves around a physics homework problem involving an electron in an electric field between parallel plates. Participants express confusion regarding the acceleration needed to stop the electron and question the clarity of the problem statement. There is uncertainty about the source of the acceleration, as any opposing force could theoretically stop the electron if applied long enough. The trajectory of the electron is also debated, with concerns that it may not stop unless it collides with a plate. Overall, the participants seek clarification on the problem's wording and intent.
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Homework Statement
An electron enters an electric field between two horizontal parallel plates with a speed of 4.00 x 106 m/s. The electric field between the plates is 175 V/m. The distance (y) between the plates is 30 cm
Relevant Equations
Determine the acceleration required to bring the electron to a stop.
Select one:
a. 9.81 m/s2
b. 3.6 x10-24 m/s2
c. 3.1 x 1013 m/s2
d. 2.8 x 106 m/s2

Determine the distance the electron travels into the plates before stopping.
Select one:
a. 0.27 m
b. 0.35 m
c. 0.13 m
d. 0.26 m
im not sure if it’s “d” for question 1 and if it’s b for question 2...
 
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nolife123 said:
Homework Statement:: An electron enters an electric field between two horizontal parallel plates with a speed of 4.00 x 106 m/s. The electric field between the plates is 175 V/m. The distance (y) between the plates is 30 cm
Relevant Equations:: Determine the acceleration required to bring the electron to a stop.
Select one:
a. 9.81 m/s2
b. 3.6 x10-24 m/s2
c. 3.1 x 1013 m/s2
d. 2.8 x 106 m/s2

Determine the distance the electron travels into the plates before stopping.
Select one:
a. 0.27 m
b. 0.35 m
c. 0.13 m
d. 0.26 m

im not sure if it’s “d” for question 1 and if it’s b for question 2...
How did you calculate those answers?
 
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nolife123 said:
Homework Statement:: An electron enters an electric field between two horizontal parallel plates with a speed of 4.00 x 106 m/s. The electric field between the plates is 175 V/m. The distance (y) between the plates is 30 cm
Relevant Equations:: Determine the acceleration required to bring the electron to a stop.
I have no idea what the question is asking.

Any acceleration will bring it to a stop if applied against the velocity for a sufficient period. But where is this acceleration coming from?
We have enough information to determine the trajectory of the electron (I assume its initial velocity is parallel to the plates), and based on that it is not going to stop unless it hits a plate. (We don't know where in the gap it is injected.)

So the question seems to be referring to some other force being applied, but if so it should be asking for a force, not an acceleration.

Is this the question exact wording of the question as given to you? Is it a translation?
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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