Step-by-step explanation:
It is given that, Jill and George both push on the same cart with 20 units of force, but in opposite directions.
We know that when two forces are acting in opposite direction, they cancel out each other.
Net force in this case = +20 N - 20 N = 0
It means the net force is 0. As a result, the cart will not move. The forces acting on the cart are balanced.