91Ó°ÊÓ

The first body exerts a force on the second body, and the second body exerts an equal and opposite force on the first body.

${\stackrel{\mathbf{→}}{\mathbf{F}}}_{\mathbf{1}}\mathbf{2}\mathbf{=}\mathbf{-}{\stackrel{\mathbf{→}}{\mathbf{F}}}_{\mathbf{2}}\mathbf{1}$

This action and reaction of forces act on different bodies. These forces act on each other as long the objects are in contact.

The push P exerted by you will always equal the reaction force F on you. These two forces are acting on two different bodies. On the object, only push P is exerted by you, and the object will exert an equal force on you in the opposite direction.

And now, if it is moving at constant velocity (zero acceleration), then there is no push P on the object and, as a result, no reaction force F on you. Hence both will be zero in this case.

If the object accelerates, P exerted by you will always be equal to the reaction force F on you, as explained above.