# Math Help - physics

1. ## physics

You are told that the volume of a sphere is given by V=pie d3/4, where V is the volume and d is the diameter of the sphere. Is this equation dimensionally correct? Use SI unit analysis to find out.

2. well the dimension of d is length. [L]

3/4 and pi are dimensionless so the dimension of 3/4d^3 is [L]^3 which is the dimensions of volume.

3. Originally Posted by cruzangyal
You are told that the volume of a sphere is given by V=pie d3/4, where V is the volume and d is the diameter of the sphere. Is this equation dimensionally correct? Use SI unit analysis to find out.
Please clarify the purported formula, do you mean:

$
V=\pi d^3/4
$

which is dimensionally OK, or:

$
V=\pi d~\frac{3}{4}
$

which is not.

RonL

4. Yeah, I missed that

if its d, then its wrong

if its d^3 then its fine.

5. Originally Posted by CaptainBlack
Please clarify the purported formula, do you mean:

$
V=\pi d^3/4
$
I think she meant this one.