The penalty for "sin" had to be physical and emotional becuse it signifies the work that Jeseu came to do in the world for we are no longer now connected to Him by emotions and phyical but by the Spirit wi the help of the Holy Spirit.

Jesus penalty for sin  involved physical and Emotional pain because as it is written that man was made in the image of God and Jesus was God and since God had send many prophet on the earth to save it but many did not take the words of the prophet seriously so Jesus came to suffer physically and emotionally so that those who saw could believe that although we go through many sufferings but through trusting in God and believing that Jesus suffered and died for us to be forgiven.

The physical suffering was to help all those to belief and trust in God. Before Jesus started suffering he said that the "Will of God be done but not His Will" and it is also clear that Jesus asked for Forgiveness for his tormentors and It is quoted in the scriptures did not know what they were doing.

Jesus came into the world as a man with physical and emotional feelings so inorder for him to accomplish his mission of redeeming the sins of mankind , he had to go through those pain as a human being.

the sin that jesus came to attone are physially commited by physical men.so threrfore jesus have to die physically for physical men so the justice of sin can bbe perfected.