Physics Question?

[taki]

A student performs Coulomb's classic experiment. Shes adds Y coulomb of positive charge to a small metal sphere that is suspended by a thread. Shes adds X coulomb of positive charge to a small metal sphere that is held on a glass rod. She positions the X coulomb sphere as indicated in the diagram and because like charges repel eachother the Y coulomb sphere is pushed out to the right.

Calculate the mass of the Y coulomb spere. hint:It is bigger than you might guess.

angle=30 degrees
X = 3
Y = 6
l\
l \ 30 cm
l \
l \
O O
X Y

[taki]

Ok maybe someone know how distance, coulomb force, and mass is related?

[Pyrotex]

Originally Posted by taki

Ok maybe someone know how distance, coulomb force, and mass is related?

Let me dust off my favorite Physics text book. What fun!!

[taki]

Can someone tell me if this is right?

30 cm = 0.3 m
(0.3m)(tan 30) = 0.17 m (distance)

F= (9.0x10^9N.m^2C^-2)(3.00 C)(6.00 C)/ (0.17m^2) = 5.6e12 N

(coulomb's law)^^

1N = 1 kg*m/s^2

F=mg
m = F/g
m = (5.6e12 kg*m/s^2)/(9.8 m/s^2) = 5.7e11 kg

[taki]

Anyone? Maybe someone can tell me if I am to determine the mass, do I only consider the forces in the x-direction. Or the sum of the forces in both directions. I would think F=mg would be enough to relate the coulmb force sphere Y "feels" and mass of the sphere. However I think maybe the tension should be considered. Someone please help.

[taki]

Anyone know about Coulomb's law, mass, distance?

[Jay-qu]

Ok buddy, slow down, your questions will be answered, you just need to give us some time

From what I can surmise of your diagram, the Y sphere has been pushed out and now subtends a 30 degree angle with the vertical - is this correct?

Yes 30cm is .3m

[taki]

Originally Posted by Jay-qu

Ok buddy, slow down, your questions will be answered, you just need to give us some time

From what I can surmise of your diagram, the Y sphere has been pushed out and now subtends a 30 degree angle with the vertical - is this correct?

Yes 30cm is .3m

Yes, sorry the diagram is not so good.

[Jay-qu]

Assuming a few things along the way, this is what I have got to:

[Jay-qu]

LOL

accidently did the wrong one..