Help hw question driving me crazy

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The discussion revolves around a homework question involving the calculation of electric field using potential difference and distance measurements. The user is confused about how to apply absolute and relative error calculations to determine the electric field, particularly whether to double the error of the potentials. They provide specific voltage measurements and their associated errors, along with a distance measurement, seeking clarity on the steps outlined in the hint. A similar problem is referenced to illustrate the process, but the user remains uncertain about the correct approach. The conversation highlights the challenges of applying error analysis in physics calculations.
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help... urgent homework question driving me crazy!

Hi. I don't understand this homework question... and I mean I know that I have to use the absolute error and relative error for it, but I don't understand how to find the electric field with the potential difference and distance... I've been looking at it for a while now, and it's due in an hour. This is driving me nuts! Can anyone please help?

You measure 2 potentials and estimate their errors, (1.1+-0.028)V and 0.4V with the same error. You determine the potential difference between these voltages. With the measured distance of (5.543+-0.245)cm between the points where the voltages were measured and the potential difference you calculate the electric field in the region between the 2 points. What is the absolute error of the electric field (hint: calculate the absolute error of the voltage difference, convert it and the absolute error of the distance given to relative errors, calculate the relative error of the electric field, and then convert that to an absolute error.

I'm trying to follow the hint step-by-step, but do I have to double the error of the potentials? I don't know... I'm lost.
 
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one more thing

If it helps, a similar problem, just with different numbers, but with the correct answer, is below.

You measure 2 potentials and estimate their errors, (1.1+-0.022)V and 0.4V with the same error. You determine the potential difference between these voltages. With the measured distance of (4.895+-0.212)cm between the points where the voltages were measured and the potential difference you calculate the electric field in the region between the 2 points. What is the absolute error of the electric field ?

ans: .8874515
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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