Calculating Work on a Falling Raindrop

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The discussion revolves around calculating the work done by gravity on a 1.9 mg raindrop falling from a height of 2500 m. The user applied the formula W = FΔx, using the mass converted to kilograms and the acceleration due to gravity as 9.8 m/s², resulting in an answer of 0.04655 J. However, this answer was marked incorrect, prompting the user to seek clarification on potential errors. Suggestions included verifying if the problem required approximating gravity as 10 m/s² and consulting the instructor for further guidance. The conversation emphasizes the importance of understanding problem requirements and instructor input in resolving discrepancies in physics calculations.
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1. The problem statement, all variables, and given/known data
How much work does gravity do on a 1.9-mg raindrop as the drop falls to the ground from a cloud 2500 m above the ground?

Homework Equations


W = FΔx
F = ma

The Attempt at a Solution


I thought this problem would be pretty straightforward since I'd just use the equation for work directly. Δx is given as 2500 m. The mass of the raindrop is 1.9 mg which I converted to 1.9*10^-6 kg. Lastly, the acceleration is due to gravity so it is 9.8 m/s^2.

W = (1.9*10^-6 kg) * (9.8 m/s^2) * (2500 m)
= 0.04655 J

I got 0.04655 J and the site I'm doing these problems on states that my answer is incorrect. I'm not sure where I went wrong?
 
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I agree with your answer and there is no room for round off errors here. Do you know what the correct answer is?
 
kuruman said:
I agree with your answer and there is no room for round off errors here. Do you know what the correct answer is?

Unfortunately I do not. I have 1 attempt left to answer the question correctly and afterwards they'll tell me the correct answer.
 
Somewhere there may be an instruction that g be approximated by 10ms2[/size], perhaps?
 
Your instructor is the final arbiter and can override any scoring made by an algorithm. Take your answer to your instructor and ask what is wrong with it before you try your last attempt.
 
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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