The required amount of heat for heating a steel bar is determined by the formula:
Q = C * m * (t2 – t1), where C is the specific heat capacity of steel (according to table C = 500 J / (K * kg)), m is the mass of the steel bar taken (m = 30 kg), t2 is the temperature of the bar after heating (t2 = 1220 ºС), t1 is the temperature of the bar before heating (t1 = 20 ºС).
Let’s perform the calculation:
Q = 500 * 30 * (1220 – 20) = 500 * 30 * 1200 = 18,000,000 J or 18 MJ.
Answer: Heating a steel bar requires 18 MJ of heat.
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