# Lab Question (spring formula)

1. Oct 17, 2005

### SS2006

i have this error formula

1/2 (change in m/m + change in k/k) * square root of m/k

now my question is

the m in the m/k is that in kg or grams

and the m in the change in m/m is that in grams or kg

my classmates are having mixed results, im confused, want to kow the real way
thanks

2. Oct 17, 2005

### SS2006

the real formula were trying to prove

2 (pie) * root of m/k

the m was in KG so im assuming in the error its in KG too right

3. Oct 18, 2005

### SS2006

noone ?!

4. Oct 18, 2005

Hey, I believe the formula you have is one used to calculate the period of an oscillating mass-spring system.

Anyway, in order to obtain clear working, we normally express all physical quantities in SI units. The SI unit for mass is kg, and I suppose if you used kg as the unit for mass in your calculations, the error will also be in kg.

Hope this helps!

5. Oct 18, 2005

### lightgrav

Delta m / m is unitless ... so is Delta k /k !
They must be, because you add them!

By the way: HERE, Delta means "uncertainty", not change.