Answer:
[tex][/tex] The work done by a coolie (or anyone carrying a load) is considered zero when walking bec work is defined as the product of force and displacement in the direction of the force. When a coolie walks with a load on their back, the force exerted by the coolie is in the vertical direction (to support the load against gravity) while the displacement is in the horizontal direction (the direction of walking). Since the force and displacement are perpendicular to each other, the work done is zero. In simpler terms, the coolie is not doing any work on the load itself - they are just carrying it from one place to another without applying a force in the direction of motion.
