Net Force: In physics, net force refers to the vector sum of all individual forces acting on an object. It determines the overall effect of these forces on the object's motion.
Frictional Force: Frictional force opposes the motion between two surfaces in contact. If there was friction between the shopping cart and one of its wheels, it would affect how easily it moves when pushed.
Applied Force: An applied force is any external force exerted on an object by another object or person. In this case, "Force F" represents an applied force on the shopping cart's handle.