phyiscs, help help help?

Question

An aluminum rod is 20.0 cm long at 20°C and has a mass of 350 g. If 14500 J of energy is added to the rod by heat, what is the change in length of the rod?

Answer 1

The coefficient of thermal expansion for aluminum is 23*10^-6/ºK. The expansion is ∆L/L, so ∆L/L = 23*10^-6*∆T
∆Q = m*cp*∆T, where cp is the specific heat of aluminum = .897*J/(gr*ºK)

∆T = 14500/(350*.897)

Therefore ∆L = 20*23*10^-6*14500/(350*.897) cm

Answer 2

insufficient data. You need a constant to relate heat with length