The physics of tug of war

Concrete

Carpet

Grass

Lino

Concrete

My prediction for Concrete has the most grip because of the friction

Carpet

My prediction for the carpet is that we might slip

Grass 

My prediction for the grass is that we will slip because of the mud and the dirt and it not like the concrete were it is grip 

Lino 

My prediction for the lino is that we wont slip because of our shoes that we were wearing

concrete because it has more friction