Volume of a bowl (using variables not numbers)

Click For Summary

Homework Help Overview

The problem involves finding the volume of water in a hemispherical bowl with radius "a" filled to a depth "h". The discussion centers around setting up the integral using the disk method to calculate this volume.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the setup of the integral and the geometric representation of the bowl. There are suggestions to sketch the graph of the bowl and the water level to aid in understanding. Questions arise about the equation of the curve and the dimensions relevant to the volume calculation.

Discussion Status

Participants are actively engaging with the problem, exploring different aspects of the setup and seeking clarification on the equations involved. Some guidance has been offered regarding sketching the graph and understanding the geometry, but there is still confusion about specific equations and dimensions.

Contextual Notes

There is a mention of the depth "h" being measured from the bottom of the bowl, and participants are trying to clarify the relationship between "h" and the radius "a". The discussion reflects uncertainty about the correct mathematical representation of the bowl's shape.

htoor9
Messages
16
Reaction score
0

Homework Statement



A hemispherical bowl of radius "a" contains water to a depth "h"

Fine the volume of water in the bowl.


Homework Equations



Pi * Integral(R(x))^2

basically the disk method


The Attempt at a Solution



The answer is (Pi*h2*(3a-h))/3...i just have no idea how to set up the integral to get that. Thanks guys
 
Physics news on Phys.org
htoor9 said:

Homework Statement



A hemispherical bowl of radius "a" contains water to a depth "h"

Fine the volume of water in the bowl.


Homework Equations



Pi * Integral(R(x))^2

basically the disk method


The Attempt at a Solution



The answer is (Pi*h2*(3a-h))/3...i just have no idea how to set up the integral to get that. Thanks guys
Start by sketching a graph of the function that represents the bowl. I recommend sketching the lower half of the graph of x2 + y2 = a2 to make your computations a little simpler.

Draw a line across the bowl representing a level of h units. Since h is measured from the bottom of the bowl, if you have located the bowl as I suggested, the water level crosses the y-axis at (0, h - a). For example, if the bowl's radius is 6'' and the water is 2" deep, the water level on the y-axis is at (0, 2 - 6) = (0, -4).

Draw a typical "slice" of the water. What is its volume? That's what you will use for your integrand.
 
Mark44 said:
Start by sketching a graph of the function that represents the bowl. I recommend sketching the lower half of the graph of x2 + y2 = a2 to make your computations a little simpler.

Draw a line across the bowl representing a level of h units. Since h is measured from the bottom of the bowl, if you have located the bowl as I suggested, the water level crosses the y-axis at (0, h - a). For example, if the bowl's radius is 6'' and the water is 2" deep, the water level on the y-axis is at (0, 2 - 6) = (0, -4).

Draw a typical "slice" of the water. What is its volume? That's what you will use for your integrand.

since I'm revolving it around the y axis, how do i know what the length of the axis to the end of the bowl with the water is? I'm really confused
 
The bottom point of the bowl is at (0, -a).
 
Mark44 said:
The bottom point of the bowl is at (0, -a).

ok. i still can't figure out what the equation of the curve is... is it h^2?
 
An equation has = in it. Your graph should show the lower half of a circle whose center is at the origin, and whose radius is a. You know the equation of a circle, right?
 

Similar threads

  • · Replies 33 ·
2
Replies
33
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 20 ·
Replies
20
Views
3K
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
4K
Replies
24
Views
4K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K