Coulomb's Law and electric force

AI Thread Summary
To solve the problem using Coulomb's Law, the charge of Object A should be +5 nano-coulombs, while Object B has a charge of -5 nano-coulombs. The distance between the objects must be converted to meters, which is 0.03 m for 3.0 cm. The electric force can then be calculated using the formula F = k * |q1 * q2| / r^2, where k is Coulomb's constant. Clarifying these assumptions and ensuring proper unit conversions will lead to the correct answer.
angel_romano
Messages
5
Reaction score
0
I can't seem to figure out how to do this problem. I've tried the equation for coulomb's law, but I can't get the right answer. If somebody can just help me with setting the problem up.

Two objects ar rubbed against each other. Object B gains a charge of -5 nano-coulombs. What is the electric force between the two objects when the distance between them is 3.0 cm? Also, how do I convert the nano-coulombs to coulombs?
 
Physics news on Phys.org
angel_romano said:
I can't seem to figure out how to do this problem. I've tried the equation for coulomb's law, but I can't get the right answer. If somebody can just help me with setting the problem up.

Two objects ar rubbed against each other. Object B gains a charge of -5 nano-coulombs. What is the electric force between the two objects when the distance between them is 3.0 cm? Also, how do I convert the nano-coulombs to coulombs?

You multiply by 10^{-9}, (1 nc= 10^{-9} C).

the question si very ambiguous. *Assuming* that the two objects were initially uncharged and *assuming* that they can be treated as point charges then the answer should be given by Coulomb's law. (what did you use for the two charges? One should be +5 nc and the other -5 nc. Also, did you put the distance in meters?)

Pat
 
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...
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...
Back
Top