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:
60 comments Page 4 of 6.
Albin Antony said:
9 years 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.
Nagi said:
9 years ago
Why diameter is converted into radius?
Nagi said:
9 years ago
Please anyone say why we are taking radius instead of diameter?
Manasa said:
9 years ago
Diameter d = 2r.
Tomsy said:
9 years ago
Please, someone explain me by step by step.
Ravi said:
8 years ago
Surface area of iron cube of side 10cm is?
Junaid said:
8 years ago
Why is the internal radius 3cm?
Suba sanjeev .m said:
8 years ago
I am not getting this, can you explain clearly?
Utham said:
8 years ago
The Internal radius and external radius. given is 8g/cm^3 not for hollow space.So, the first find out the full volume that is with the use of external radius. Now subtract hollow space that volume with internal radius. R^2h*r^2h.
Ajay said:
8 years ago
Could you explain me about pi?
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