Finding the height of a cilinder.

[fawk3s]

Homework Statement

A wooden cilinder (wood's density=1400 kg/cubemeter=1.4 g/cubecm). The diameter of the bottom is 4 cm and the cilinder weights 2.4 kg. How high is it?

Homework Equations

m= ro*V
V cilinder= h * S bottom
S bottom= pi*r(squared)

The Attempt at a Solution

V = m/ro
V = 2400/1.4 = 1714,2857...~1714,29 cubecm

S bottom = 2(squared) * 3.14 = 12.56 cm(squared)

h=height
h= 1714,29/12,56 = 136,4880...~136,49 cm



Is this correct or am I missing something? Because some of my friends got 400-something for the answer. So was I or them wrong? Just can't nail it.
(I don't know the original answer.)

Thanks in advance,
fawk3s

 

[tiny-tim]

Hi fawk3s!

(have a pi: π and try using the X² tag just above the Reply box )

A wooden cilinder (wood's density=1400 kg/cubemeter=1.4 g/cubecm). The diameter of the bottom is 4 cm and the cilinder weights 2.4 kg. How high is it?
…
h= 1714,29/12,56 = 136,4880...~136,49 cm
…
Is this correct or am I missing something? Because some of my friends got 400-something for the answer. So was I or them wrong? Just can't nail it.
(I don't know the original answer.)

I make it the same as you.

(maybe your friends forgot the π ?)