The weight of a barbell acting on a weightlifter in 80 N represents Fg.
Step-by-step explanation:
Force exerted due to earth's gravity is represented as Fg. The gravitational pull is experienced by the mass of object has some force attached to by it which is called as force due to gravity.
The force is dependent upon the mass of the object experiencing the force. Hence the weight of a barbell acting on a weightlifter 80 N is the best example for Fg.