i have two maths questions in my homework im stuck on.

1.an empty 750 ml glass bottle has a mass of 89 grams when it is full of water what is its mass.

2. here are three cross sections of the same solid. cirlce,triangle and oval. name it

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- Aug 10th 2006, 04:17 AM #1

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Originally Posted by**topsquark**

Brilliant, Dan!

I had difficulty with the "oval" (ellipse) but you made it*so*obvious.

Code:A * / \ / \ / \ / *D / * \ / * \ / * \ B* - - - - - - - *C

$\displaystyle \Delta ABC$ is a side view of a circular cone (it doesn't have to be "right").

A slanted plane cut through the plane, passing through $\displaystyle B$ and $\displaystyle D$,

. . and the top portion is removed.

From the front, we see $\displaystyle \Delta BCD.$

From the top, we see a circle with diameter $\displaystyle BC.$

From the left, we see an ellipse with major axis $\displaystyle BD.$

Does this have a*name*? . . . other than "circular conical wedge"?

- Aug 10th 2006, 08:25 AM #8Originally Posted by
**Soroban**

I appreciate the comment of "brilliant" but I can't take credit for it. Any Intermediate level Mechanics book has a picture of this, owing to motion under an inverse square force law. This diagram shows the different types of orbit due to Newton's Law of Gravitation...the "conic sections." Which means you can get a parabola and a hyperbola as well, given the correct angle for the cross section. (The cone is "doubled" by continuing it through its point.)

-Dan