The discussion revolves around the concept of work in physics, specifically in the context of moving an object (a textbook) from a high shelf to a low shelf. Participants are exploring whether the work done on the object is positive or negative based on the directions of force and motion.
The discussion is active, with participants questioning the phrasing of the problem and clarifying the directions of force and motion. Some guidance has been provided regarding the relationship between force and displacement, leading to a better understanding of the concept of work.
There appears to be some confusion regarding the definitions of positive and negative work, particularly in relation to the directions of force and motion. Participants are working within the constraints of the problem as stated, without additional context or information.
The motion is upwards, the direction is downwards.brainpushups said:In what direction is the force YOU exert? Compare this with the direction of motion.
AAAA said:upwards
AAAA said:You move a textbook from a high shelf to a low shelf. Is the work you do on it positive or negative?
brainpushups said:That's not how you phrased the question:
From a high to a low shelf means the motion is downward. The force you exert is upward. Therefore the work you do is negative (force and displacement are in the opposite direction i.e. θ = 180)