A small ball weighing 0.3 μg is suspended on a thin thread and has a charge of 3 μC. What will be the tension

| April 8, 2021 | education

A small ball weighing 0.3 μg is suspended on a thin thread and has a charge of 3 μC. What will be the tension of the thread, if you bring another ball with the same charge 5 * 10 ^ -8 C from below to it at a distance of 30 cm.

The thread tension is equal to the sum of the forces acting on the thread:

F (nat) = F (gravity) – F (Coulomb).

F (heavy) = m * g = 0.3 [mKg] * 9.8 [m / s ^ 2] = 0.3 * 10 ^ (- 3) [kg] * 9.8 [m / s ^ 2] = 3 * 10 ^ (-3) [H].

According to Coulomb’s law, we define the repulsion force:

F (cool) = (k * q1 * q2) / r ^ 2.

F (cool) = (9 * 10 ^ 9 * 3 * 10 ^ (- 7) * 5 * 10 ^ (- 8)) / 0.3 ^ 2 = 1.5 * 10 ^ (- 3) [H] …

Let’s substitute everything in the first formula:

F (nat) = 3 * 10 ^ (- 3) – 1.5 * 10 ^ (- 3) = 1.5 * 10 ^ (- 3) [H] = 1.5 [mN].



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