Finding Water Depth in an Inverted Cone

In summary, the conversation discusses finding the depth of water in an inverted right circular cone with a vertical angle of 120 collecting water at a steady rate of 18∏ cm^3/min. The first question asks for the depth after 12 minutes, and the second question asks for the rate of increase of depth at this instant. The formula for the volume of a cone is suggested as a starting point for solving the problem. It is clarified that depth is a distance and not a volume or rate.
  • #1
lionely
576
2

Homework Statement


An inverted right circular cone of vertical angle 120 is collecting water from a tap at a steady rate of 18∏ cm^3/min. Find
a) the depth of water after 12min,
b) rate of increase of depth at this instant



Homework Equations





The Attempt at a Solution



All I know is that dV/dt = 18cm3/min
so shouldn't the depth after 12 mins be 12 * dv/dt?
 
Physics news on Phys.org
  • #2
lionely said:
All I know is that dV/dt = 18cm3/min
so shouldn't the depth after 12 mins be 12 * dv/dt?
.. which would imply a depth of what, 216 cm3? Anything strike you as odd about that?
 
  • #3
Well yeah that is way too much :S
 
  • #4
lionely said:
Well yeah that is way too much :S
No, I meant depth measured in cm3 (!)
 
  • #5
Depth would be dh/dt, h being that height
 
  • #6
That would give you units of cm/min, which isn't the units of depth. Based on your answer, I'm not sure you understand what the word depth means in the context of this problem.

Why don't you start by looking up the formula for the volume of a cone? Sketch a picture and tell us how the variables in the formula relate to the physical quantities in this problem.
 
  • #7
lionely said:
Depth would be dh/dt, h being that height
The depth of the water is the height of the surface measured from the point of the cone. So it's a distance, not a volume, not a rate. dh/dt would be the rate of change of the depth.
 

Related to Finding Water Depth in an Inverted Cone

1. How do you find the water depth in an inverted cone?

The water depth in an inverted cone can be found by using the formula D = (3/4) * h, where D is the depth and h is the height of the cone. This formula assumes that the top of the cone is open and the bottom is closed. If the cone is not a perfect shape, this formula may not be accurate.

2. Can the water depth in an inverted cone be measured using a ruler?

No, a ruler cannot be used to accurately measure the water depth in an inverted cone. This is because the water level in the cone would not be flat and the ruler may not reach the bottom of the cone. It is important to use the correct formula and measurements to accurately find the water depth.

3. How does the shape of the inverted cone affect the water depth?

The shape of the inverted cone can greatly affect the water depth. If the cone is not a perfect shape, the formula D = (3/4) * h may not be accurate. Additionally, if the cone is not symmetrical, the water level may not be even and could result in an inaccurate measurement.

4. Is it possible to find the water depth in an inverted cone without using a formula?

No, it is not possible to accurately find the water depth in an inverted cone without using a formula. It is important to use the correct formula and measurements to ensure an accurate result. Without a formula, the measurement may be incorrect and could lead to inaccurate data or conclusions.

5. How can I ensure an accurate measurement of the water depth in an inverted cone?

To ensure an accurate measurement of the water depth in an inverted cone, it is important to use the correct formula and measurements. Additionally, it is important to make sure the cone is a perfect shape and that the water level is even. Using multiple measurements and averaging the results can also help to increase accuracy.

Similar threads

  • Calculus and Beyond Homework Help
Replies
7
Views
2K
  • Calculus and Beyond Homework Help
Replies
2
Views
3K
  • Calculus and Beyond Homework Help
Replies
2
Views
3K
  • Calculus and Beyond Homework Help
Replies
3
Views
3K
  • Calculus and Beyond Homework Help
Replies
2
Views
2K
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
5K
  • Calculus and Beyond Homework Help
Replies
4
Views
6K
  • Calculus and Beyond Homework Help
Replies
8
Views
3K
Back
Top