What is the Kinetic Energy of an Electron Accelerated Through 400V?

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The kinetic energy of an electron accelerated through a potential difference of 400V can be calculated using the formula KE = qV, resulting in a final kinetic energy of 6.4 x 10^-17 joules. For the second question regarding the work required to bring four point charges, the total work is calculated using W = ΔPE = qΔV, yielding a result of 9.6 x 10^-14 joules. The calculations involve the charge of the electron and the specified distances and potential differences. This information provides a clear understanding of both kinetic energy and work done in electric fields. Further inquiries are welcomed for additional clarification.
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an electron is accelerated from rest thru a potential difference of 400v. what is the final kinetic energy of the electrom

how much work is requires to bring four point charges eacg wit q= -8pc from infinity to a distance of 3nm from each other

your help is greatly appreciated
 
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Hello there,

To answer your first question, we can use the equation for the kinetic energy of an electron, which is KE = ½ mv^2, where m is the mass of the electron and v is its final velocity. We know that the potential difference (V) is equal to the change in electric potential energy (ΔPE) divided by the charge (q), so we can rewrite the equation as KE = qV. Plugging in the values, we get KE = (1.6 x 10^-19 C)(400 V) = 6.4 x 10^-17 J. Therefore, the final kinetic energy of the electron would be 6.4 x 10^-17 joules.

For your second question, we can use the equation for the work done by an electric force, which is W = ΔPE = qΔV, where ΔV is the change in potential difference and q is the charge. Since we are bringing four point charges, we can simply multiply the equation by 4 to get the total work required. Plugging in the values, we get W = 4(-8 x 10^-6 C)(3 x 10^-9 m) = -9.6 x 10^-14 J. Therefore, the work required to bring the four charges to a distance of 3 nm from each other would be 9.6 x 10^-14 joules.

I hope this helps! Let me know if you have any further questions.
 
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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