I have a dog named Bailey and she's 3 years old. She's a golden retriever Rottweiler mix, so her and I often play tug of war! She'll grab on to one end of her rope and I'll whip her around with the other end. I realized that there s actually a lot of physics involved in this! Both me and Bailey are pulling on the rope and creating tension. If both Bailey and I pull on the rope and the ball doesn't move, keeping it in the same position despite our pulling, that means that the amount of force in each direction we are exerting is equal. That would then mean that the rope is at equilibrium because there is no acceleration in either direction. Also i notice that Bailey bites down very hard on her end of the rope where there is usually a knot. The amount of force Bailey puts on the rope from biting down, is the exact same amount of force, the rope exerts onto her mouth. This would be the reason her mouth might be sore from biting down so hard. Because of the force of the rope pushing back. Me and Bailey have a lot of fun playing and turns out there's actually a lot of physics involved!