Question

1.)When do action and reaction forces within a system not cancel each other?

a.)When the action force is double the resistance of friction
=b.)When the reaction force is contained in separate events
c.)Never, they always cancel each other
d.)Only on February 29th during a full moon

Answer 1

action and reaction always equal, taking into account inertia (mass*acceleration)

c is almost right, cancel is a silly ill thought word. If "cancel" means equal and opposite, then c is right.