The discussion revolves around understanding the components of work in the context of calculating net work done on a block, particularly focusing on the role of gravitational potential energy (mgh2) and its effect on kinetic energy (KE) in a closed system scenario.
The discussion is ongoing, with participants seeking clarity on the signs of work components and the treatment of the system as closed. Some guidance has been offered regarding the nature of external forces acting on the block and the implications for net work done, but no consensus has been reached.
Participants are grappling with the definitions of closed systems and the effects of external forces on kinetic energy, particularly in the context of gravitational work when moving up and down slopes.
The positive terms are those which add to the KE of the block. Will coasting uphill increase it or reduce it?Dylan R said:
Reduceharuspex said:
So what sign should it have?Dylan R said:
-haruspex said:
Treating what as a closed system? The block is certainly not a closed system by itself. It is acted on by external forces and these change its KE. But we know it starts and ends at rest, so the net work done on it is zero. Going down the slope, gravity does positive work on it, but going up the slope gravity does negative work on it.Dylan R said:
