Answer:
The angle is 18.3 degree.
Explanation:
A uniformly charged infinite plane, density σ = 4 x 10^-9 C/cm^2, is placed vertically in air. A small ball of mass 8 g, with charge q = 10^-8 C, hangs close to the plane, so that the string is initially parallel to the plane. Take g = 9.8m/s2. When in equilibrium, by what angle is the string hanging the ball to the plane?
surface charge density, σ = 4 x 10^-5 C/m^2
Charge, q = 10^-8 C
mass, m = 0.008 kg
Let the angle is A and the tension in the string is T.
The electric field due to a plane is

Now equate the forces,

Answer: c
Explanation: hope this helps :)
In order to calculate the unknown reaction force, we need to know that the sum of forces pointing down is equal the sum of the forces pointing up, so all forces will be in equilibrium.
So we have:
Answer:
Newton's Second Law of Motion states that a force on an object is equal to the mass of the object multiplied by its acceleration (F=ma). ... When the punter kicks the ball, his foot exerts a force on the ball. The football then exerts an equal amount of force in the opposite direction on the kicker's foot.