The weak nuclear force
repulsive force
Force acts on charges. This is demonstrated by Coulomb's law.
an attractive force that acts between protons and neutrons
Gravity
Electrical force actually acts on electrical charges.
A neutron is made of 3 quarks, namely an up quark and two down quarks. It is this composition of quarks that cause it to have zero charge. (An up quark has a charge of 2/3 and down quarks have a charge of -1/3 - thus 2/3 + (-1/3 *2) = 0) A free neutron (that is one that is not bound in a nucleus) will become a proton, an electron and an electron-neutrino. This happens through the weak force (it acts on a down quark, turning into an up). This does not mean a neutron contains an electron. It does not. Yes, an electron appears when a neutron decays, but that electron does not exist in the neutron as an electron, but it does not.
I think it might be electrostatic force! This is the force that acts between the particles!
repulsive force
an attractive force that acts between protons and neutrons
Force acts on charges. This is demonstrated by Coulomb's law.
Gravity
The electrical field force acts between two charges, in the same way that the gravitational field force acts between two masses.
Electrical force actually acts on electrical charges.
Magnetism
Friction
Friction
Acceleration = force/mass