# Calculating acceleration with slug and lbs

1. Oct 11, 2012

### tratata

1. The problem statement, all variables and given/known data

What is the acceleration when a 30.0 lb force acts on a 12.2 slug mass?

2. Relevant equations
a=F/m

3. The attempt at a solution

I can't quite figure out the slug thing. I took 12.2 slugs to be 392.5 lb/ft/s2
Then divided 30 by 392.5 lbs got cancelled out and I'm left with ft/s2 in denominator which the is reversed because we are dividing fractions ??? Is this right? I get 7.6 x 10 -2 ft/s2
Thanks a million!!!!

Last edited: Oct 11, 2012
2. Oct 11, 2012

### Sourabh N

According to Wikipedia, 1 slug = 1 lbf/ft/s2.

3. Oct 11, 2012

### tiny-tim

hi tratata!
no, you don't need to convert …

the whole point of using slugs is to keep things simple …

F = ma works fine if the mass is in slugs and the force is in lb-force

from the pf library on slug
In Europe, a slug is one of many varieties of gastropod mollusc.

In English-speaking countries, it is a unit of mass, equal to g pounds-mass (i.e., 32.17405 lbm). It is the amount of mass that will accelerate at one foot per second squared when one pound-force is applied.

It can be thought of as a pound-weight divided by 1 ft/s².

It is mostly used when "pound" is used to mean a force, and avoids the need of an extra constant in Newton's second law $\mathbf{F}\ =\ m\mathbf{a}$.

It is a unit in the gravitational foot-pound-second (fps) system.​

4. Oct 11, 2012

### tratata

Hi tiny-tim! Thanks for your response! If a=F/m and I don't need to convert then I divide 12.2 by 30 I get 0.41 - where lbs gets cancelled out and I'm left with ft/s2? Does that seem right? Thanks!!!

5. Oct 12, 2012

### tiny-tim

hi tratata!

(just got up :zzz:)
wouldn't it be better to divide the force by the mass?

6. Oct 14, 2012

### tratata

It sure would )))))))

7. Jun 18, 2013

hello

hey guys i want to become a scientist and i need lessons

8. Jun 18, 2013

### SteamKing

Staff Emeritus
That's what school is for.

9. Jul 8, 2013

### TheDemx27

I've been using the internet for quite some time. I haven't become old enough for my first high school physics/chemistry class but that doesn't mean the the information isn't out there. Wikipedia is your friend.

Also this is a good site: https://www.khanacademy.org/science/physics