A cast iron rod has a mass of 240g. Its cross sectional area is 10cm squared and its density is 7.5g/cmcubed. caluclate the volume (which i have done) and the length which im stuck on!!!
2006-09-12 04:52:17 · 21 answers · asked by Tina H 1 in Science & Mathematics ➔ Mathematics
The length is the volume divided by the cross sectional area.
There's nothing wrong with helping your daughter but make sure she understands it, otherwise you helping is a complete waste of time.
2006-09-12 04:55:23 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Volume = Mass/ Density = 240/7.5 = 32 cm cubed (did you get that?)
Volume = area of cross section x length (if it's a prism, that is a shape with the same cross section all the way through)
Length = volume/area of cross-section= 32 / 10 = 3.2 cm
Make sure she understands this-a diagram may help for the second part.
2006-09-12 18:02:28 · answer #2 · answered by astephens29 3 · 0⤊ 0⤋
The cross sectional area is 2 dimensional, the volume is 3 dimensional. To get the length, divide the volume by the cross-sectional area. You said you'd worked out the volume and they've already given you the cross-sectional area.
I got 3.2cm as the length and 32cm cubed as the volume.
2006-09-12 15:30:57 · answer #3 · answered by Katri-Mills 4 · 0⤊ 0⤋
I'm not sure what cross sectional area it's refering to. Does it have a picture? Is it across the length of the rod? I'm guessing it is, and I'm guessing you have to derive from the volume and the cross sectional area. I don't remember what is the formula for calculating the area of a rod. But the cross section area is the legth times the diameter. If you can find from the volume of the rod the diameter, you have your length.
Well, by the answers given while I wrote mine, I was wrong, and your problem is simpler than I was making it...
2006-09-12 12:02:51 · answer #4 · answered by dahfna 3 · 0⤊ 1⤋
Easy—you're halfway there!
Volume is measured in cm cubed, cross-sectional area in cm squared. So to find the length (measured in cm), all you have to do is divide the volume you've calculated by the area you've been given. (Ignore all the answers talking about pi, you only need that if you haven't been given the cross-sectional area.)
i.e. 240/7.5 = 32 cm cubed volume, 32/10 = 3.2 cm length
2006-09-12 12:03:17 · answer #5 · answered by tjs282 6 · 0⤊ 0⤋
Simple math:
volume = mass/density = 240/7.5 = 32cm cubed
length = volume/(cross sectional area) = 32/10 = 3.2cm
simple if u know how . . . .
2006-09-13 09:25:44 · answer #6 · answered by sims 1 · 0⤊ 0⤋
Mass of the cast iron rod = 240 gm
Area of the cast iron rod =10 cm^2
Length of the cast iron rod = x cm
Volume of the cast iron rod = 10x cm^3
Density of the cast iron rod = 7.5 gm/cm^3
Using the formula mas
Mass= (Volume )(Density)
240 = (10 x)(7.5)
On solving
x = (240)/(7.5)(10)
x =3.2 cm
Therefore length of the rod = 3.2 cm
2006-09-12 12:11:44 · answer #7 · answered by Amar Soni 7 · 0⤊ 1⤋
Volume = Area x length... SO if you already have the volume, just divide by area.
2006-09-12 13:35:21 · answer #8 · answered by kingofclubs_uk 4 · 0⤊ 0⤋
Volume is 32cm. If the cross-sectional area is 10cm2 then it's length is 3.2cm. (vol of any regular object is cross-section x length)
2006-09-12 13:43:40 · answer #9 · answered by cyberpat1957 1 · 0⤊ 0⤋
Volume is the area of the base x height (or in this case length)
Area of the based is pie x r(squared) which is 3.142 x 25
divide the volume by this and you have your length
2006-09-12 11:56:24 · answer #10 · answered by slug dance 2 · 1⤊ 2⤋