Question

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction, with no other forces present. Which of the following statements are true just before they are about to collide?

They are closer to the to the initial position of the electron that to the initial position of the proton.

They are closer to the to the initial position of the proton that to the initial position of the electron.

The electrostatic force on the proton is greater than the electrostatic force on the electron.

They both have the same speed.

They are at the midpoint of their initial separation.

Answer 1

we know that the electron an proton are of having charge of equal in magnitude but opposite charges

e = -1.6*10^-19 C,

proton e = +1.6*10^-19 C

From coulomb's law of forces

the elecic force between tow charges separated by a distance is proportional to the product of their charges and inverslly proportioinal to the square of the distance between them

F = kq1*q2/r^2

here the mass of the proton is greater than mass of electron

so

From Newton's second law of motion  

F = m*a

so the

They are closer to the to the initial position of the proton that to the initial position of the electron

second option is correct