What is the net force if you push a cart to the right with 5n of force, and a friend pushes the cart to the left with 5n of

0 newtons

Explanation: If you push a cart to the right with 5 newtons of force to the right and a friend pushes the cart 5 newtons to the left, there will be no motion.

To understand this further, take a look at the image I provided. I provided two arrows one of the left and on on the right. If two people are pushing on the cart with the same amount of force, the net force will be 0 so it will be a balanced force. When we have a balanced force, there's no motion.