Answer:
Tension, T = 0.0115 N
Explanation:
Given that,
Mass of the plastic ball, m = 1.1 g
Length of the string, l = 56 cm
A charged rod brought near the ball exerts a horizontal electrical force F on it, causing the ball to swing out to a 21.0 degree angle and remain there. According to attached figure :
[tex]T\cos\theta=mg[/tex]
T is tension in the string
[tex]T=\dfrac{mg}{\cos\theta}\\\\T=\dfrac{1.1\times 10^{-3}\times 9.8}{\cos(21)}\\\\T=0.0115\ N[/tex]
So, the tension in the string is 0.0115 N.
