# Homework Help: Kilogram Newtons (Extremely Easy Question!)

1. May 17, 2006

### kape

Very sorry, but I just don't know..

If there is a 5kg load on an object, let's say a book on a table.. what is it's force in kgN? Is it 5kg x 9.8?!

2. May 17, 2006

### Staff: Mentor

Yes, the weight of a 5kg mass is about 5*9.8 = 49 Newtons.

3. May 18, 2006

### jasc15

maybe he is getting at the difference between kgm and kgf (kilogram mass and kilogram force)?

4. May 18, 2006

### Staff: Mentor

Good point.

If by "5 Kg load" you mean the weight of an object whose mass is 5 Kg, then find the force via w = mg. The load equals (approximately) 5*9.8 = 49 N as I stated above.

On the other had, if by "5 Kg load" you really meant a load (force) of 5 kgf (Kilogram-force, a unit of force, not mass), then convert to standard (SI) units of force (Newtons) using the definition of 1 kgf = 9.80665 N.

Of course, for many purposes either one is close enough.

Note: kgN is not a unit (that I am aware of). Mass is measured in kg (also called kgm for kilogram-mass); force is measured in N (or kgf, for kilogram-force).