Question

Two similar metal spheres are suspended by silk threads from the same point. When the spheres are given equal charges of 2uC the distance between them becomes 6cm. If length of each thread is 5cm, the mass of each sphere is ? (g=10m/s2)

1. 3kg
2. 4kg
3.
4.​

Answer 1

Given:

Two similar metal spheres are suspended by silk threads from the same point. When the spheres are given equal charges of 2uC the distance between them becomes 6cm.

To find:

Mass of each sphere

Calculation:

Considering Free-Body Diagram of one sphere:

$1) \: T \sin( \theta) = F \: \: \sf{and} \\2) \: T \cos( \theta) = mg$

Dividing 1) and 2)

$\therefore \: \tan( \theta) = \dfrac{F}{mg}$

$= > \dfrac{3}{4} = \dfrac{ \frac{9 \times {10}^{9} \times {(2 \times {10}^{ - 6} )}^{2} }{ {(0.06)}^{2} } }{m \times 10}$

$= > \dfrac{3}{4} = \dfrac{36 \times {10}^{ - 3} }{m \times 36 \times {10}^{ - 3} }$

$= > \dfrac{3}{4} = \dfrac{1 }{m }$

$= > m = \dfrac{4}{3}$

$= > m = 1.33 \: kg$

So , final answer is :

Mass of the spheres is 1.33 kg.

Answer 2

Explanation:

1.33 kg is the answer

hope it will help you