Aforce can exist between two charged particles or objects even if they're as small as subatomic particles. between which of these would no force exist? select one: a. proton-proton b. neutron-proton c. electron-electron d. proton-electron

The force between particles can be an electrical force because of their charges, and a gravitational force because of their masses.

Protons, neutrons, and electrons all have mass, so all of the choices (a, b, c, d) have gravitational forces between them.

Neutrons don't have any electrical charge, so there's no electrical force in choice-b .

prolly a beacuse the momentuem the car has increases while going down hill