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Keeping that in mind. I am wondering how long it would take to reach 240 feet. My math is really bad so I really can't figure it out for myself. Can anybody help me out?

Thanks in advance

donsgal

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5,398 Posts

Keeping that in mind. I am wondering how long it would take to reach 240 feet. My math is really bad so I really can't figure it out for myself. Can anybody help me out?

Thanks in advance

donsgal

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v = 0 so

x = g * t ^2

t^2 = x/g

t = squareroot (x/g)

x = 240 feet

g = 32 feet/second^2

t = squareroot (240 feet /32 feet/second^2)

t = squareroot (7.5 second^2)

t = 2.7386 seconds

neglecting air resistance

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Oh my! I have REALLY been out of college too long!suburbanite said:

v = 0 so

x = g * t ^2

t^2 = x/g

t = squareroot (x/g)

x = 240 feet

g = 32 feet/second^2

t = squareroot (240 feet /32 feet/second^2)

t = squareroot (7.5 second^2)

t = 2.7386 seconds

neglecting air resistance

Seriously though, I entered as engineering and ended in Anthropology.

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Donsgal, just call it an even 3 seconds.

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donsgal said:

Keeping that in mind. I am wondering how long it would take to reach 240 feet. My math is really bad so I really can't figure it out for myself. Can anybody help me out?

Thanks in advance

donsgal

the correct number is 9.8 m (32 feet) per second squared in a vacuum.

The formula for distance is

d = (1/2)9.8(m/s2)t2

so 240ft = 73.152m

73.152=(1/2)9.8(m/s2)t2

so solving for t, you get 3.863803772 seconds

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Actually. closer to 4. Your previous calculation is incorrect. It time zero, the speed is zero, at time 1 speed is 32ft/s Avg speed for first second is 16ft/s.suburbanite said:Donsgal, just call it an even 3 seconds.

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I left out the 1/2 in front of the g* t^2.

That changes the result to 3.6 seconds though, which still disagrees with your result.

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That's because your using 32ft/s and I'm using 9.8m/s. You'd think they'd be equal but 32 ft equals 9.7536. So I think it's rounding.suburbanite said:

I left out the 1/2 in front of the g* t^2.

That changes the result to 3.6 seconds though, which still disagrees with your result.

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Thanks Deacon.

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If you're trying to figure out how far down your water is, forget the math. We tried it and it just didn't work; no matter what we did, the rock bounced off the side of the casing a couple of times on the way down and that kept messing with the math. Instead, what we did was buy one of those alarms people put next to the water heater - it beeps when it gets wet, cost $12 at Lowes. We tied it to a long line and lowered it down the well. When we heard the beep, we marked the line and pulled it up then measured the line.

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No one would use the "math method" to determine the distance to the water level in their well. A logical person would simply tie a washer or bolt to some kite string and drop it down the well casing.coalroadcabin said:

If you're trying to figure out how far down your water is, forget the math. We tried it and it just didn't work; no matter what we did, the rock bounced off the side of the casing a couple of times on the way down and that kept messing with the math. Instead, what we did was buy one of those alarms people put next to the water heater - it beeps when it gets wet, cost $12 at Lowes. We tied it to a long line and lowered it down the well. When we heard the beep, we marked the line and pulled it up then measured the line.

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Cabin Fever said:No one would use the "math method" to determine the distance to the water level in their well. A logical person would simply tie a washer or bolt to some kite string and drop it down the well casing.

Guess I was misunderstanding the reason for donsgal's question then. :shrug:

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I dont think she gave a reason. She just asked how long it would take for a rock to fall 240 feetcoalroadcabin said:Guess I was misunderstanding the reason for donsgal's question then. :shrug:

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michiganfarmer said:I dont think she gave a reason. She just asked how long it would take for a rock to fall 240 feet

I was just assuming. For the life of me, I can't figure any other reason for the question.

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No, lead time. Of course now she needs to calculate how fast her husband is walkingsuburbanite said:

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