Final answer:
When carrying a box at a constant speed in a flat hallway, no work is done on the box because there is no displacement in the direction of your applied force; thus, the answer is B. No, 0 J of work.
Step-by-step explanation:
If you are carrying a 50 N box down a flat hallway at a constant speed, you are not doing any work on the box in the physics sense. In physics, work is defined as the force applied to an object times the distance moved by that object in the direction of the force. Since the box is not moving in the direction of the applied force (up or down if you are just holding it), but rather is moving horizontally while the force you apply is vertical, the work done is zero. The correct answer to whether you are doing any work would be: B. No, 0 J of work.
In physics, for work to be done, two criteria must be satisfied: a force must be applied, and the object must move a distance in the direction of that force. While the box is in motion, the movement is perpendicular to the gravitational force you're counteracting by holding it up; thus, there's no displacement in the direction of your applied force. Using the equation Work (W) = Force (F) × Distance (d) × cos(θ), where θ is the angle between the force and displacement, we see that cos(90°) = 0; this makes the work done zero because the force you apply is perpendicular to the motion.