Jawabanmu

2014-04-15T18:39:59+07:00
Dik :
Q = 84 Kj =) 84000 Joule
m = 500 gram =) 0,5 Kg
t₁ = 20°C
c = 4.200 J/(Kg.K)

Dit : t₂ = ?

Penyelesaian :

Δt = Q/m . kalor jenis
( t2 - t1 ) = 8400/ 0,5 . 4200
( t2 - 20) = 40 
t2 = 40+20
t2 = 60°C

2014-04-15T18:49:00+07:00
Q = m . c . ΔT
Q = m . c . (T2 - T1)
84000 = 0,5 . 4200 .(T2 - 20)
84000 = 2100T2 - 42000
84000+42000=2100T2
126000=2100t2
T2=60 c