Electrostatics Deflection Problem

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Paper dust can interfere with inkjet printer operation by introducing additional charged particles that disrupt the intended flow of ink droplets. The charged dust may affect the electrostatic forces acting on the ink droplets, leading to misalignment or malfunction. For the second part of the problem, the user is struggling to visualize the charging and deflection process of the ink drops as they pass through the electric field between the plates. They recognize the need to apply kinematic equations to determine the charge acquired by each drop. Overall, the discussion highlights the complexities of electrostatics in inkjet printing and the challenges in solving related physics problems.
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Homework Statement
In inkjet printing, a rapidly moving nozzle horizontally squirts drops of ink that form letters and images on paper. A common problem is horizontal white lines running through the print due to a clogged nozzle. Another common problem is paper dust.

(a) Within the context of electrostatics, explain why paper dust can cause an inkjet printer to malfunction.
(b) Suppose the ink drops have a mass m = 2.00 x 10^-11 kg each and suppose the magnitude of the velocity at which they horizontally travel is 30 m/s. The drops pass through a charging unit that gives each drop a positive charge q by causing it to lose some electrons. The drops then pass between parallel deflecting plates of length D = 2.20 x 10^-2 m, where there is a uniform vertical electric field with magnitude E = 8.6 x 10^4 N/C. If a drop is deflected a distance d = 3.30 x 10^-3 m, what magnitude of charge q does each drop acquire by the time it reaches the end of the deflection plate? The density of ink is 1,000 kg/m^3; assume the effects of gravity are negligible.

Possible relevant equations
y(t) = 1/2at^2
x(t) = vt
E = kQq/r^2
F = qE = ma

The attempt at a solution
(a)
. My thought process for this question was that there is a possibility that the dust particles are also charged in some manner. Therefore, the movement of these other outsider charges causes interference with the printer.
(b). I'm having a hard time picturing the drop passing through a charging unit and the deflection that occurs between the two parallel plates. I tried to look up diagrams in my textbook that depict a similarly described scenario, but there was nothing relevant. I also have a feeling that I'm going to have to apply some kinematic equations to also be able to solve part of this question.

Any help would be greatly appreciated! :)
 
Last edited:
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This problem has been solved :)
 
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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