The graph above shows how a $0\mathrm{.}66-$kg sample cools down with time. If heat is constantly being removed at $2\mathrm{.}21$W$,$ what is the specific heat capacity of the sample? First pick any two points on the graph: convert the time difference for those two points into an energy difference by the relation between power and energy. This energy is the heat transfer, so finally, relate the heat transfer to the temperature difference between the two points, using the relations in the reading.