Reading a scale as a function of time (need formula)

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SUMMARY

The discussion focuses on deriving a formula for the scale reading as a function of time when water is added to a pan from a faucet at a height of 3.1 meters, with a flow rate of 0.16 kg/s. The correct formula for the scale reading for time t greater than sqrt(2h/g) is gR(t - sqrt(2h/g)) + R*sqrt(2gh), where g is the acceleration due to gravity. Participants clarify that the variable h is not needed in the final formula, emphasizing the importance of correctly evaluating the scale reading at t=sqrt(2h/g>.

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pinkybear
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Homework Statement


A scale is adjusted so that when a large, shallow pan is placed on it, it reads zero. A water faucet at height h = 3.1 m above is turned on at t=0 and water falls into the pan at a rate R = 0.16 kg/s.

Determine a formula for the scale reading as a function of time t for t > sqrt(2h/g).
Express in terms using some or all of the variables: h,R,t

AND

Replace the pan with a tall narrow cylindrical container with Area of 11 cm^2 and find reading for t=9.2 s

The Attempt at a Solution


I got this
g*R*(t-sqrt(2h/g))+R*sqrt(2gh)
but it says i don't need the h variable, I'm stuck..

...the function of time is the time it takes for the water to fall 3.1 meters plus the rate times time?
 
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pinkybear said:

The Attempt at a Solution


I got this
g*R*(t-sqrt(2h/g))+R*sqrt(2gh)
but it says i don't need the h variable, I'm stuck..

...the function of time is the time it takes for the water to fall 3.1 meters plus the rate times time?
One problem with your formula is that it gives the incorrect reading at t=sqrt(2h/g). What should the reading be at that time, and what does your formula give for the reading?
 

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