Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 5)
5.
A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:
Answer: Option
Explanation:
External radius = 4 cm,
Internal radius = 3 cm.
| Volume of iron |
|
||||||
|
|||||||
| = 462 cm3. |
cm3
Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.
Discussion:
61 comments Page 4 of 7.
Albin Antony said:
1 decade ago
Volume = base area * height.
For calculating, base area of the given hollow cylinder, we should remove the area containing thickness from the original.
So (pi * 4^2) - (pi*3^2) = pi* (4^2 - 3^2) = Effective base area.
For calculating, base area of the given hollow cylinder, we should remove the area containing thickness from the original.
So (pi * 4^2) - (pi*3^2) = pi* (4^2 - 3^2) = Effective base area.
Aliza mir said:
1 decade ago
@Sai Dileep. The formula for volume to be applied here is the cylinder.
@Rajadurai. Since the pipe is hollow so the internal part is being subtracted from the total thickness, which is the radius.
@Rajadurai. Since the pipe is hollow so the internal part is being subtracted from the total thickness, which is the radius.
Sai dileep said:
1 decade ago
What is the formula for calculating the volume of this problem?
Sibi said:
1 decade ago
@Divya as per formula, it means cylinder volume is,
pi*r^2h, here it is a hollow cylinder we have to subtract external diameter to internal diameter.
pi*r^2h, here it is a hollow cylinder we have to subtract external diameter to internal diameter.
Avani said:
1 decade ago
Same doubt @Rajadurai.
Thuru said:
1 decade ago
I don't understand this.
Is there any easy way to understand this?
Is there any easy way to understand this?
Rajadurai said:
1 decade ago
Why [4]^2 - [3]^2 while calculating volume?
Anyone please explain this step.
Anyone please explain this step.
Sanjay said:
1 decade ago
1 hectares is equal to how many cm cube?
Sanoop said:
1 decade ago
How comes 462*8 gm?
S.Vijay said:
1 decade ago
Tell me the formula of this problem?
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