Final answer:
The total work done by a weightlifter walking 2 meters with an 800 N object on their head is zero with respect to the force of gravity, assuming horizontal walking without inclination and no displacement in the vertical direction.
Step-by-step explanation:
For the weightlifter walking through 2 meters with an object that has a weight of 800 N, the total work done in walking the 2 m distance can be calculated using the formula W = F × d × cos(θ), where W is work, F is the force applied, d is the distance through which the force is applied, and θ is the angle between the force and the direction of motion. Since the weightlifter is moving horizontally while holding the weight, the force due to gravity is acting downwards and not in the direction of the motion, therefore, the work done by the weightlifter against gravity is zero, as there is no displacement in the direction of the gravitational force. However, although work against gravity is zero, the weightlifter may be doing work against other forces like friction or air resistance if these are present. But with the information given, it is safe to assume that the total work done with respect to moving the object horizontally is zero without considering other external forces.