When soccer players run they are using friction to propell themselves
Answer=8N
Explantion:
20-20=0
22-14=8N
Answer: the wall contracts the force exerted by his head. The wall produces the opposite force which is equal to the force his head bangs the wall with.
Explanation: if his head exerts a much greater force than the wall can counteract the wall will be destroyed, if the wall exerts a much greater force than his head exerts he will be pushed far back and might even suffer a broken head.
The wall in this case provides the opposite reactive force.
Its b i literally have had this exact question