Water leaking from box and the relationship of volume and height.
$begingroup$
Suppose we have a container that has a base of area $b$ and we fill it up with water.
Volume of water = $b cdot h$, where $h$ is height.
Hence, $mathrm{d}v/mathrm{d}t = b cdot mathrm{d}h/mathrm{d}t$.
The container has a small hole of area $a$ at the bottom corner and so water is constantly leaking.
From my research:
1) I found that $mathrm{d}v/mathrm{d}t = -a cdot $ velocity of water.
2) Velocity = $sqrt{2gh}$ where $g$ is the gravitational constant.
And so $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$.
Initially I did this:
$mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh} = B * mathrm{d}h/mathrm{d}t$
$1/sqrt{h}mathrm{d}h = -a sqrt{2g}/b mathrm{d}t$
Integrate both sides
$2sqrt{h} = -a sqrt{2g}/b cdot t$
$h = (a^2 cdot g)/(2b^2) cdot t^2$
But this doesn't make sense.
I realise though that the $h$ from $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$ is also constantly changing but I'm still not sure what to do. I tried deriving the equation again but it did not get me anywhere.
I want to find the function how much height or volume has decreased after time t. Can someone help?
calculus integration functions derivatives physics
$endgroup$
add a comment |
$begingroup$
Suppose we have a container that has a base of area $b$ and we fill it up with water.
Volume of water = $b cdot h$, where $h$ is height.
Hence, $mathrm{d}v/mathrm{d}t = b cdot mathrm{d}h/mathrm{d}t$.
The container has a small hole of area $a$ at the bottom corner and so water is constantly leaking.
From my research:
1) I found that $mathrm{d}v/mathrm{d}t = -a cdot $ velocity of water.
2) Velocity = $sqrt{2gh}$ where $g$ is the gravitational constant.
And so $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$.
Initially I did this:
$mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh} = B * mathrm{d}h/mathrm{d}t$
$1/sqrt{h}mathrm{d}h = -a sqrt{2g}/b mathrm{d}t$
Integrate both sides
$2sqrt{h} = -a sqrt{2g}/b cdot t$
$h = (a^2 cdot g)/(2b^2) cdot t^2$
But this doesn't make sense.
I realise though that the $h$ from $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$ is also constantly changing but I'm still not sure what to do. I tried deriving the equation again but it did not get me anywhere.
I want to find the function how much height or volume has decreased after time t. Can someone help?
calculus integration functions derivatives physics
$endgroup$
$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28
add a comment |
$begingroup$
Suppose we have a container that has a base of area $b$ and we fill it up with water.
Volume of water = $b cdot h$, where $h$ is height.
Hence, $mathrm{d}v/mathrm{d}t = b cdot mathrm{d}h/mathrm{d}t$.
The container has a small hole of area $a$ at the bottom corner and so water is constantly leaking.
From my research:
1) I found that $mathrm{d}v/mathrm{d}t = -a cdot $ velocity of water.
2) Velocity = $sqrt{2gh}$ where $g$ is the gravitational constant.
And so $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$.
Initially I did this:
$mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh} = B * mathrm{d}h/mathrm{d}t$
$1/sqrt{h}mathrm{d}h = -a sqrt{2g}/b mathrm{d}t$
Integrate both sides
$2sqrt{h} = -a sqrt{2g}/b cdot t$
$h = (a^2 cdot g)/(2b^2) cdot t^2$
But this doesn't make sense.
I realise though that the $h$ from $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$ is also constantly changing but I'm still not sure what to do. I tried deriving the equation again but it did not get me anywhere.
I want to find the function how much height or volume has decreased after time t. Can someone help?
calculus integration functions derivatives physics
$endgroup$
Suppose we have a container that has a base of area $b$ and we fill it up with water.
Volume of water = $b cdot h$, where $h$ is height.
Hence, $mathrm{d}v/mathrm{d}t = b cdot mathrm{d}h/mathrm{d}t$.
The container has a small hole of area $a$ at the bottom corner and so water is constantly leaking.
From my research:
1) I found that $mathrm{d}v/mathrm{d}t = -a cdot $ velocity of water.
2) Velocity = $sqrt{2gh}$ where $g$ is the gravitational constant.
And so $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$.
Initially I did this:
$mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh} = B * mathrm{d}h/mathrm{d}t$
$1/sqrt{h}mathrm{d}h = -a sqrt{2g}/b mathrm{d}t$
Integrate both sides
$2sqrt{h} = -a sqrt{2g}/b cdot t$
$h = (a^2 cdot g)/(2b^2) cdot t^2$
But this doesn't make sense.
I realise though that the $h$ from $mathrm{d}v/mathrm{d}t = -a cdot sqrt{2gh}$ is also constantly changing but I'm still not sure what to do. I tried deriving the equation again but it did not get me anywhere.
I want to find the function how much height or volume has decreased after time t. Can someone help?
calculus integration functions derivatives physics
calculus integration functions derivatives physics
edited Feb 10 '15 at 15:31
Unknown7
asked Feb 10 '15 at 12:06
Unknown7Unknown7
61
61
$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28
add a comment |
$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28
$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
$$huge {rm Toricelli's;Law}\large v=sqrt{frac{2{rm gh}}{1-a^2/b^2}}approxsqrt{2{rm gh}}tag{$all bequiv (a/b)to0$}$$
where $rm a,b,v,g,h$ are cross-section area of hole ,base area of cylinder, velocity of water from hole, Acceleration due to gravity and Height of the liquid above the hole.
This can be derived using equation of continuity:
$$av=bV$$
where $V$ is speed of horizontal surface of water. And Bernoulli's equation:
$$rm P+frac12rho v^2+rho gh= constant$$
where $rm P,rho,v,g,h$ are Pressure,Density,Velocity,Acceleration due to gravity and Height of the point of the liquid where we are calculating the constant.
I believe this can also be derived by Energy Conservation.
$endgroup$
add a comment |
$begingroup$
$frac{dV}{dt} = a sqrt{2gy}$
$frac{asqrt{2g} dt}{A} = -frac{1}{sqrt{y}} dy $
Upon integration we get $t=frac{Asqrt{2h}}{asqrt{g}}$
Where $a$ is cross section area of hole and $A$ is cross section of tank $h$ is the height till which water is filled.
$endgroup$
add a comment |
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2 Answers
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2 Answers
2
active
oldest
votes
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$begingroup$
$$huge {rm Toricelli's;Law}\large v=sqrt{frac{2{rm gh}}{1-a^2/b^2}}approxsqrt{2{rm gh}}tag{$all bequiv (a/b)to0$}$$
where $rm a,b,v,g,h$ are cross-section area of hole ,base area of cylinder, velocity of water from hole, Acceleration due to gravity and Height of the liquid above the hole.
This can be derived using equation of continuity:
$$av=bV$$
where $V$ is speed of horizontal surface of water. And Bernoulli's equation:
$$rm P+frac12rho v^2+rho gh= constant$$
where $rm P,rho,v,g,h$ are Pressure,Density,Velocity,Acceleration due to gravity and Height of the point of the liquid where we are calculating the constant.
I believe this can also be derived by Energy Conservation.
$endgroup$
add a comment |
$begingroup$
$$huge {rm Toricelli's;Law}\large v=sqrt{frac{2{rm gh}}{1-a^2/b^2}}approxsqrt{2{rm gh}}tag{$all bequiv (a/b)to0$}$$
where $rm a,b,v,g,h$ are cross-section area of hole ,base area of cylinder, velocity of water from hole, Acceleration due to gravity and Height of the liquid above the hole.
This can be derived using equation of continuity:
$$av=bV$$
where $V$ is speed of horizontal surface of water. And Bernoulli's equation:
$$rm P+frac12rho v^2+rho gh= constant$$
where $rm P,rho,v,g,h$ are Pressure,Density,Velocity,Acceleration due to gravity and Height of the point of the liquid where we are calculating the constant.
I believe this can also be derived by Energy Conservation.
$endgroup$
add a comment |
$begingroup$
$$huge {rm Toricelli's;Law}\large v=sqrt{frac{2{rm gh}}{1-a^2/b^2}}approxsqrt{2{rm gh}}tag{$all bequiv (a/b)to0$}$$
where $rm a,b,v,g,h$ are cross-section area of hole ,base area of cylinder, velocity of water from hole, Acceleration due to gravity and Height of the liquid above the hole.
This can be derived using equation of continuity:
$$av=bV$$
where $V$ is speed of horizontal surface of water. And Bernoulli's equation:
$$rm P+frac12rho v^2+rho gh= constant$$
where $rm P,rho,v,g,h$ are Pressure,Density,Velocity,Acceleration due to gravity and Height of the point of the liquid where we are calculating the constant.
I believe this can also be derived by Energy Conservation.
$endgroup$
$$huge {rm Toricelli's;Law}\large v=sqrt{frac{2{rm gh}}{1-a^2/b^2}}approxsqrt{2{rm gh}}tag{$all bequiv (a/b)to0$}$$
where $rm a,b,v,g,h$ are cross-section area of hole ,base area of cylinder, velocity of water from hole, Acceleration due to gravity and Height of the liquid above the hole.
This can be derived using equation of continuity:
$$av=bV$$
where $V$ is speed of horizontal surface of water. And Bernoulli's equation:
$$rm P+frac12rho v^2+rho gh= constant$$
where $rm P,rho,v,g,h$ are Pressure,Density,Velocity,Acceleration due to gravity and Height of the point of the liquid where we are calculating the constant.
I believe this can also be derived by Energy Conservation.
edited Feb 10 '15 at 20:52
answered Feb 10 '15 at 12:14
RE60KRE60K
14k22155
14k22155
add a comment |
add a comment |
$begingroup$
$frac{dV}{dt} = a sqrt{2gy}$
$frac{asqrt{2g} dt}{A} = -frac{1}{sqrt{y}} dy $
Upon integration we get $t=frac{Asqrt{2h}}{asqrt{g}}$
Where $a$ is cross section area of hole and $A$ is cross section of tank $h$ is the height till which water is filled.
$endgroup$
add a comment |
$begingroup$
$frac{dV}{dt} = a sqrt{2gy}$
$frac{asqrt{2g} dt}{A} = -frac{1}{sqrt{y}} dy $
Upon integration we get $t=frac{Asqrt{2h}}{asqrt{g}}$
Where $a$ is cross section area of hole and $A$ is cross section of tank $h$ is the height till which water is filled.
$endgroup$
add a comment |
$begingroup$
$frac{dV}{dt} = a sqrt{2gy}$
$frac{asqrt{2g} dt}{A} = -frac{1}{sqrt{y}} dy $
Upon integration we get $t=frac{Asqrt{2h}}{asqrt{g}}$
Where $a$ is cross section area of hole and $A$ is cross section of tank $h$ is the height till which water is filled.
$endgroup$
$frac{dV}{dt} = a sqrt{2gy}$
$frac{asqrt{2g} dt}{A} = -frac{1}{sqrt{y}} dy $
Upon integration we get $t=frac{Asqrt{2h}}{asqrt{g}}$
Where $a$ is cross section area of hole and $A$ is cross section of tank $h$ is the height till which water is filled.
edited Dec 3 '18 at 16:03
Math Girl
631318
631318
answered Dec 3 '18 at 15:40
user622450user622450
1
1
add a comment |
add a comment |
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$begingroup$
You'll also have to use the equation of continuity.
$endgroup$
– Gokul
Feb 10 '15 at 15:48
$begingroup$
equation of continuity? can you please elaborate?
$endgroup$
– Unknown7
Feb 10 '15 at 15:54
$begingroup$
Do you know how Torricelli's law is derived? If no, how do you know the velocity of efflux is $sqrt{2gh}$? The law (for water flowing out of a container) is derived by using the equation of continuity. Read here
$endgroup$
– Gokul
Feb 10 '15 at 15:58
$begingroup$
Sweet! Thank you so much
$endgroup$
– Unknown7
Feb 10 '15 at 16:28