Solving a Sphere Problem: Help Needed for Physics Assignment

In summary, the conversation is about a person trying to solve a physics problem, but struggling due to language barriers and difficulty with formulas. They ask for help finding the angle of a thread holding a charged sphere between two plates, and a member provides guidance on finding the electric field and relating it to the voltage and forces acting on the sphere.
  • #1
hrappur2
9
0
Hello everyone!

I'm trying to solve some physics problems for my school and I'm very bad at it. I've only 1 problem left and I would appreciate it if you guys could point me in the right direction. But I want to say that I'm not from an English speaking country so I'll have to translate the problem, it could be hard but I will try my best.

So here it is:

There is a little sphere with the mass 25g and 50nC, it hangs vertically on a thread between two plates and there is 10cm between the plates. Then 131 V are put on the plates so that the sphere pulls(?) to one of the plates. What angle does the thread of the ball (or and the ball) make? (The last sentence has wrong grammar in my own language so it could be wrong but I hope you can understand it).

-Thanks in advance!
 
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  • #2
Hi hrappur,

See attached picture. Is that the problem?

Show what you think about the problem. What forces act on the ball?

ehild
 

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  • #3
Thanks for your reply ehild!
I'm trying to figure this out but I just can't, if stuff doesn't fit perfectly into formulas I just get so lost :(

I got some ideas but they are probably stupid. Should I find what E is and than find s to find how long the ball has moved?
 
  • #4
Show what you think.
Yes, find E first.
The resultant of the electric force and gravity is opposite to the force of tension in the string. The yellow angles are equal. How is the angle related to the forces?

ehild
 
  • #5
I can't figure this out :(
 
  • #6
Do you know the electric field?

ehild
 
  • #7
is it E = k(Q/r^2) = (9*10^9)*((50*10^-9)/(10*10^-2)^2) = 4,5*10^4 N/C?
 
  • #8
It is the electric field around a point charge. Here you need the electric field between the parallel plates. This electric field acts on the charge of little sphere.

Given the voltage (131 V) between the plates which are 10 cm apart. The field is homogeneous. How are the voltage and electric field related?

ehild
 
  • #9
So E = V/d and than F = qE? Well I don't know
 
  • #10
hrappur2 said:
So E = V/d and than F = qE?
That looks right.
 

FAQ: Solving a Sphere Problem: Help Needed for Physics Assignment

What is the formula for finding the volume of a sphere?

The formula for finding the volume of a sphere is V = 4/3 * π * r^3, where π is approximately 3.14 and r is the radius of the sphere.

How do you find the surface area of a sphere?

The formula for finding the surface area of a sphere is A = 4 * π * r^2, where π is approximately 3.14 and r is the radius of the sphere.

Can you explain the difference between a sphere and a circle?

A sphere is a three-dimensional shape with all points on its surface equidistant from its center. A circle, on the other hand, is a two-dimensional shape with all points on its circumference equidistant from its center.

How can I calculate the diameter of a sphere?

The diameter of a sphere is equal to twice the radius, so you can calculate the diameter by multiplying the radius by 2.

How would you use the volume and surface area formulas to solve a real-life problem involving a sphere?

You can use the volume and surface area formulas to solve real-life problems such as finding the amount of paint needed to cover a spherical object or calculating the air or water displacement of a spherical container.

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