Magnitude of force to change direction or stop a moving object.

I am researching an issue I need explained in my chapter on blocking techniques in my book on the science behind fighting techniques.

I am calling to all readers of this blog and beyond.

Please explain in biomechanical/mechanical/physics terms why it takes less force to deflect an object than to stop an object. Please be technical in your explanation. If you wish privacy, please email me at jfcoles101@gmail.com.