Two identical, small insulating balls are suspended by separate 0.29-m threads t

Question

Two identical, small insulating balls are suspended by separate 0.29-m threads that are attached to a common point on the ceiling. Each ball has a mass of 6.4

Two identical, small insulating balls are suspended by separate 0.29-m threads that are attached to a common point on the ceiling. Each ball has a mass of 6.4 x? 10^-4kg. Initially the balls are uncharged and hang straight down. They are then given identical positive charges and, as a result, spread apart with an angle of 42 degree between the threads. Determine (a) the charge on each ball and (b) the tension in the threads. a. ?--------------Units C b. ?--------------Units N

Explanation / Answer

The forces along x on each ball is

Fx = k q1 q2/r^2 - Tx = 0

where, q1 = q2 = Q = the charge given to them
k = 8.99E9 N m^2/C^2
r = distance between them = 2Lsin(42/2) = 0.20785 m

Thus,

Tx = kQ^2/0.20785^2

Meanwhile, along y,

Fy = 0 = Ty - mg

where m = mass of one ball.

Thus,

Ty = mg = 6.272E-3 N

As

Ty = Tcos21

Then

T = Ty/cos21 = 6.718*10^-3 N   [ANSWER, PART B]

******************

Meanwhile, as

Tx = Tsin21 = 2.4076E-3 N = kQ^2/0.20785^2

Solving for Q,

Q = 1.076*10^-7 C    [ANSWER, PART A]

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.