Finding the mass of a sphere with uniform charge density

AI Thread Summary
To find the mass of a sphere with uniform charge density that levitates above an infinite sheet with surface charge density, the net force on the sphere must be zero. The volume of the sphere is calculated using the formula 4/3 pi R^3, where R is the radius. The force acting on the sphere is equal to its weight, which can be expressed using the equation F=ma, but since the sphere is stationary, acceleration is zero. The gravitational force must be balanced by the electrostatic force from the sheet. Understanding these forces is crucial to solving for the sphere's mass.
ghost34
Messages
5
Reaction score
0

Homework Statement


The sphere has radius R, and uniform volume charge density P. This sphere remains stationary (levitates) when placed above an infinite sheet of paper with a uniform surface charge density u. What is this sphere's mass?

Homework Equations


4/3 pi R^3 is the volume of a sphere
F=ma

The Attempt at a Solution


The only connection between mass and the charged situation I can see is with the Force=ma law, but as there isn't any acceleration, I can't figure out how to solve for m...any help would be appreciated, thanks
 
Last edited:
Physics news on Phys.org
To remain stationary, the net force on the ball should be zero. What are the forces acting on the ball?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

How Do You Calculate Charge Density in a Uniform Sphere?
Replies
1
Views
2K
Charge on a grounded conducting sphere in a uniform electric field, after ungrounding and movement
Replies
1
Views
1K
Induced charge on a conducting sphere sliced by a plane
Replies
2
Views
1K
Pressure versus stress in uniformly charged sphere
Replies
11
Views
1K
Charge rearrangement on conducting spheres
Replies
21
Views
4K
Electric field external to Conducting Hollow Sphere with charge inside
Replies
23
Views
3K
Calculating Linear Charge Density of a Cylinder
Replies
1
Views
2K
Electric field & force due to charged insulating hemispherical shells
Replies
12
Views
2K
Kinetic and potential energy of a particle attracted by charged sphere
Replies
6
Views
1K
How to Rank Charge Density of Conductive Spheres?
2
Replies
61
Views
5K

Hot Threads

Recent Insights

Back
Top