please help and explain those question

1./ 4) Explain why two balloons rubbed on hair will then repel each other. 6) Explain why a neutral dust particle is attracted to your shirt or the television, for example. The force of attraction between two charged Ping-PongTM balls is 2.8 x 10 4 N. If the charges are +8.0 nC and -12.0 nC, how far apart are their centres? 3 Three point charges, A (+2.0 HC), B (+4.0 HC) + 2 and C (-6.0 uC), sit consecutively in a line. If A and B are separated by 1.0 m and B and Care separated by 1.0 m, what is the net force on each charge? In the Bohr model of the hydrogen atom, an electron orbits a proton at a radius of approximately 5.3 x 10-11 m. Compare the grav- itational and the electrostatic forces between the proton and the electron. i.e. How many times greater is the electrostatic Force? f = kq, 42 r2