[" The statement "acceleration is "],[" zero if and only if the net force "],[" is zero" is valid in "]

The net force acting is not zero on

The net force acting is not zero on

In net force on a system is zero then

a) In a frame of reference S( though the net force is zero, the net acceleration is not zero. b) In a frame of reference S_2 though the net force is not zero, the net acceleration is zero. c) In a frame of reference S_3 the net acceleration is zero whenever the net force is zero.

a) In a frame of reference S_1 ( though the net force is zero, the net acceleration is not zero. b) In a frame of reference S_2 though the net force is not zero, the net acceleration is zero. c) In a frame of reference S_3 the net acceleration is zero whenever the net force is zero.

In which of the following cases the net force is not zero ?

In which of the following cases the net force is not zero ?

In which of the following cases the net force is zero .