Jawabanmu

2014-04-20T18:59:59+07:00
Q = m.c.delta t
Q = 0,25 kg * 4200 J/kg oC * 30 oC
Q = 31500 J

semoga membantu
2014-04-20T20:32:16+07:00
Q=Qab+Qbc =mxcxdeltaT+mxU =0,25x4.200x70+0,25x2.260.000 =73.500+565.000 =638.500J maaf jika salah.