A 0.400 kg sample is placed in a cooling apparatus that removes

energy as heat at a constant rate. Figure 18-32 gives the temperature

T of the sample versus time t; the horizontal scale is set by

ts
80.0 min. The sample freezes during the energy removal. The specific heat of the sample in its initial liquid phase is 3000 J/kg 

K.

What are (a) the sample’s heat of fusion and (b) its specific heat in

the frozen phase?