Heating tape puzzle

[nh3simman]

Here is a practical brainteaser for you to try.

I have a steel drum and need to keep it warm. The outside diameter is 500mm and the length is 10m. I decide that in the 10m length there should be 5 full circuits.
http://www.technisolve.co.za/images/heatertape.png
Can you tell me the length of the heater tape?

[chillin out]

7853.98163397448mm ?

Oh wait, I just got the length without going from one end to the other.

Chillin:) :)

[NoNickName]

2 * pi * radius * turns = 7850mm plus loose ends for your convenience

[Tony]

Do you need a new calculator?

I make your sum 15,720 mm plus bits at end!!!!!!!!!!!!!!

[NoNickName]

2 * 3.14 * 250 * 5 = 7850mm. Do you need a new medical treatment?

[taz24]

Can you tell me the length of the heater tape?


This much. [ ] x5

taz holds his arms out simulateing this size of the cylinder.:D

taz

[frank]

If the diameter is 500mm then the circumference is .5 *Pi = 1.57m

If the vessel is 10m long with 5 full turns of tape then 1 full turn = 2m

So, using Pythagarus, each tape length = sq rt of 1.57^2 + 2^2 = 2.54m

Therefore, total length of heater tape = 2.54 x 5 = 12.72m

[chillin out]

Just worked it out properly and came up with the same as Frank.

Well done for getting there 1st.

Chillin:) :)

[NoNickName]

If the diameter is 500mm then the circumference is .5 *Pi = 1.57m

If the vessel is 10m long with 5 full turns of tape then 1 full turn = 2m



Oh, yes, the advancement shift must be considered as well. The drawing was deceptive.

[nh3simman]

Good answer Frank.

[Tony]

Sorry Nonickname, got confused with the length of the drum and the number of turns. :(