Volume by Slicing: A cylindrical wedge, help needed please

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Homework Help Overview

The problem involves finding the volume of a curved wedge cut from a cylinder with a radius of 3m, defined by two intersecting planes—one perpendicular to the cylinder's axis and the other at a 45-degree angle. The original poster seeks to determine the area of a rectangular cross-section as a function of x for integration purposes.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to express the area of the rectangle in terms of x, noting the vertical sides as y=x/2, while questioning the function for the horizontal sides. Some participants suggest the utility of drawing a diagram to clarify the problem setup.

Discussion Status

Participants are engaged in exploring the problem, with some providing suggestions for visual aids. There is an acknowledgment of potential ambiguity regarding whether the back half of the wedge should be included in the volume calculation, indicating a productive direction in the discussion.

Contextual Notes

Participants note the lack of explicit information regarding the back half of the wedge, which may affect the final volume calculation. The original poster is also considering how to present their findings based on the information provided.

RolloJarvis
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Homework Statement


Find the volume of curved wedge that is cut from a cylinder of radius 3m by two planes. One plane perpendicular to the axis of the cylinder, the other plane crosses the first plane at a 45 degree angle at the centre of the cylinder.

(Hint: let the line of intersection of the two planes be the y-axis and then the cross section of the slice is a rectangle whose area you need to find as a function of x)

Homework Equations



V = \int^{b}_{a}A(x) dx

The Attempt at a Solution



I need to find the area of the rectangle described above as a function of x so i can integrate it to find the volume.

The length of the vertical sides of the rectangle will given by the function y=x/2, and i presume the horizontal sides would be some function involving sin, seeing as is starts at 0, ends at 0, and has a maximum or 2r in the middle of the cylinder... but i can't figure it out. this is the bit I am stuck on.

Thanks for the help!
 
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It's always a good idea to draw a picture. Maybe this will help

wedgesection.jpg


It isn't clear from your post whether you also want the back half, which would double the answer.
 
LCKurtz said:
It's always a good idea to draw a picture. Maybe this will help

wedgesection.jpg


It isn't clear from your post whether you also want the back half, which would double the answer.

of course! that makes a lot more sense with the picture, out of curiosity, what program did you use to draw the diagram? I do a lot of lab reports and a good drawing package would be very useful.

I will post a new attempt at an answer when i get the chance.

in regards to the back half also, I am unsure as all the information i have been given is written above. i guess i will just write each half = ... explicitly on the answer sheet.
 
RolloJarvis said:
of course! that makes a lot more sense with the picture, out of curiosity, what program did you use to draw the diagram? I do a lot of lab reports and a good drawing package would be very useful.

It's called Mayura Draw:

http://www.mayura.com/
 

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