Two small balls, each of mass 5.0 g, are attached to silk threads 50 cm long, which are in turn tied to the same point on the ceiling, as shown below. when the balls are given the same charge q, the threads hang at 5.0° to the vertical, as shown below. what is the magnitude of q? what are the signs of the two charges?

In triangle ABC

Sin5 = BC/AC

BC = (AC) Sin5

BC = (50) Sin5 = 4.36 cm

r = distance between the two balls = 2 BC = 2 x 4.36 = 8.72 cm = 0.0872 m

q = charge on each ball

m = mass of each ball = 5 g = 0.005 kg

electric force between the two balls is given as

F =

using equilibrium of force in vertical direction

T Cos5 = mg eq-2

Using equilibrium of force in horizontal direction

T Sin5 = F eq-3

dividing eq-3 by eq-2

T Sin5 /(T Cos5) = F/mg

F = mg tan5

using eq-1

= mg tan5

inserting the values

= 0.005 x 9.8

q = 2.03 x 10⁻⁷ C

sign of charge is same on both the balls. either it is negative or positive

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force