Calculate the Mass of a Ball Bearing (Millikan Experiment)

[rkimbel]

1. Homework Statement
You are given twelve cans (one of which is empty) which are filled with a certain number of ball bearings. Using nothing more than a balance, calculate the mass of a single bearing


2. Homework Equations
Total Mass=Mo+n(mo)
Where total mass=mass of ball bearings
Mo=smallest mass
n=number of bearings
mo= mass of each bearing

3. The Attempt at a Solution
I realize the equation above is a little confusing (formatting in PF is not easy). The way I attempted this problem was by first trying to organize the mass of the twelve cans (after subtracting the mass of the empty can, of course). I found the smallest difference between two masses, which was 2.3 g. From this point, however, I'm not sure what to do. I could possible divide each mass by 2.3 g, giving me the theoretical number of ball bearings. But I don't see how I could verify my answer. Any help is appreciated. Thank you.

 

[member 553083]

Your approach is on the right track. You are almost there. Instead of dividing each mass by 2.3 g, you need to subtract the smallest mass from each of the masses and then divide the result by 2.3 g. This will give you the number of ball bearings for each of the cans. Then simply add these numbers together and you will have the total number of ball bearings. Divide the total mass (from step 1) by the total number of ball bearings and you will have the mass of a single bearing.