Question

A boxer can hit a heavy bag with great force. why can't he hit a piece of tissue paper in midair with the same amount of force? a boxer can hit a heavy bag with great force. why can't he hit a piece of tissue paper in midair with the same amount of force? the boxer can only hit the tissue paper with a force as large as the tissue paper can exert on the boxer, and the low-mass tissue can only exert a weak force. the tissue paper can only exert a force on the boxer as large as the air resistance force exerts on the paper. the low-mass tissue exerts a smaller reaction force on the boxer than the action force the boxer exerts on the tissue. the low-mass tissue floating in the air exerts no reaction force on the boxer.

Answer 1

The boxer can just hit the tissue paper with a force as extensive as the tissue paper can apply on the boxer, and the low mass tissue can just apply a weak force.  

Let a boxer hitting on heavy bag. The boxer hits the bag while the bag hits back on the boxer and stops its movement. A pair of forces is engaged with the hitting the bag. The force pair can be quite large.  

Now considering boxer hitting a bit of tissue paper. The boxer can just apply as much force on the tissue paper as the tissue paper can apply on the boxer.  

The boxer can`t apply any force whatsoever except if what is being hit applies a similar amount of force back. An interaction requires a pair of forces acting on two separate objects.