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physics
15/f - I really need help with a physics question my teacher gave me. Weve already gone over it, but i wasnt at school, so now he wont tell me how to work it out and what the answer is even though i need to know bc i was absent. Here it is:
"The information on a Party Balloon kit containing a tank of Helium states how many of each size balloon you can expect to fill from the tank. The label states that the tank will fill THIRTY 9-inch balloons. You plan to use 11-inch balloons instead of 9" ones, so how many can you expect to be able to fill?"
can anyone please solve this and tell me how to work it? I'd really REALLY appreciate it.
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Doing it with a ratio is easier, BL4CKB3L7_F41RY. 30/x=11/9, 24 balloons. Also, most balloons aren't perfect spheres, so a ratio is more accurate.
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My solution is formed on the basis that the balloons are spherical in shape, and that the measurement refers to the diameter.
First, you want to find how much volume the helium will fill.
Equation for volume of a sphere is 4/3(pi)(r^3)
You have your diameter, so you can find r (d/2 = 4.5")
We'll call this volume V, because I don't have a calculator :)
So, now you have the volume of one balloon. Multiply V by 30, and you have the total volume of helium available.
Call this V2.
Now, use the same method as above to find the volume of one 11" balloon. It's easy; just substitute 5.5" instead of 4.5" for the radius.
Call this volume V3.
Divide V2 by V3 to find the number of 11" balloons you can fill.
And there you have it!
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30/x=11/9. Cross multiply and divide, 24 balloons, with about half a balloon worth of helium to spare.
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