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PHYSICS HOMEWORK HELP: Electric Charges.?
There are three particles in a straight line that each have the exact same charge. Particle A is 3cm from particle B, particle B is 1cm from particle C. The electric force exerted by particle A on particle B is 4 x 10-2 N. What is the force exerted by particle C on particle B?
Please tell me how exactly I have to solve this question, I've been stuck on it for a while.
2 Answers
- ?Lv 76 years agoFavorite Answer
You know the distance between A and B and the force between A and B; you can use Coulomb's law to find the charges on A and B, which are "the exact same."
F = kQq / d²
0.04 N = 8.99e9N·m²/C² * Q² / (0.03m)²
Wait, forget about that. We don't need it. We know the charges are all the same; and we know that the force that results when the particles are 3 cm apart is 0.04 N. Then by the inverse-square-of-distance law, the force is 3² times as great when the separation is 1/3 as large; the force between C and B is 0.36 N. ◄
OK, if you want to continue on the way I started, then solve for Q.
Q = 6.33e-8 C
Then when the separation is 1 cm,
F = 8.99e9N·m²/C² * (6.33e-8C)² / (0.01m)² = 0.36 N ◄
Hope this helps!
