The electric field between the plates of a parallel-plate capacitor is horizontal, uniform, and has a magnitude E. A small object with a charge of -2.12
is attached to the string. The tension in the string is 0.310 
, and the angle it makes with the vertical is 12 
.What is the mass of the object?
What is the magnitude of the electric field?
Not sure where to even begin here.... help?
Hmmm... I couldn't do this one either. But if anything comes up, I'll be sure to reply back here. Btw, whose blog is this? How can we use it?
ReplyDeleteI figured it out! Its very similar to example 19-6 "dangling by a thread" on page 645 of the book. You basically look at it as a free body diagram. The forces acting on the charge are the tension in the string, the electric field, and gravity. The object is not in motion so the sum of the forces equals zero.. if you Split it into the x and y components you will get:
ReplyDeletefor the y component:
Tcos(12degrees)- mg = 0
for the x component:
Tsin(12degrees)-qE = 0
Then you solve for E and m.
**btw**
This is the Physics blog for the Phys 2bg class at Mt.Sac.. its hosted by the SI Dante! I think you just need to become a member then you can post any questions and he or one of our classmates can help!