Three identical blocks move in three different settings. Block A moves on a horizontal surface, block B moves up an inclined plane, and block C moves down an inclined plane. They all start with the same speed and continue until brought to rest by friction. Rank which block dissipates more mechanical energy by friction, least to greatest. I am not very good with these "conceptual" questions, so I'm having a hard time even finding out where to start. I've been trying to calculate the forces of friction for each block (e.g. fA = u * mg, fB = u * mg * cos(T), etc) but it hasn't helped much. So, I was hoping somebody could at least give me a push in the right direction.