The discussion revolves around the concept of work in physics, specifically addressing the signs of work done by different forces in a scenario involving a pump lifting water. Participants are exploring the conditions under which work is considered positive or negative, particularly in relation to the direction of force and motion.
The discussion is active, with participants providing insights into the nature of work done by the pump and gravity. Some guidance has been offered regarding the need to specify which work is being calculated, and the distinction between positive work done by the pump and negative work done by gravity has been highlighted.
There is a mention of a homework statement that includes specific parameters, such as the mass of water, depth, and speed, which may influence the calculations and interpretations of work. Participants are also noting the importance of clearly stating the question to avoid ambiguity.
You can't get a negative number by multiplying positive numbers. Your equation represents force and displacement in the same direction. The force is positive and the displacement is positive.Ineedhelpwithphysics said:Homework Statement: A pump is required to lift 850 kg
of water per minute from a well 14.7 m
deep and eject it with a speed of 17.7 m/s
Relevant Equations: W = F*d
W = delta KE
Im confused I did
850*9.8*14.7 = 1.2x10^5
Why is it not negative since the force is opposite to the motion?