Physic Heat 30

A 4m x 5m x 7m room is heated by the radiator of a steam heating at rate of 10 000 kJ/ h and a fan is used to distribute the warm air in the room. The average rate of heat loss from the room is estimated to be about 5000 kJ/h. If the initial temperature of the air is 10 degree Celsius, estimate how long it will take for the air temperature to rise to 20 degree Celsius. Take the density and the specific heat capacity for air as 1.2 kg m^-3 and 1000 J /kg degree Celsius
THX!!!!

更新1:

physics8801: thank you for answering my question. But can you explain these steps to me? Net heat input into the room = 10 000 kJ/h - 5 000 kJ/h = 5000 kJ/h Heat required to heat up the air from 10'C to 20'C = 168 x 1000 x (20-10) J = 1 680 000 J = 1680 kJ

更新2:

Hence time required = 1680/5000 hr. = 0.336 hr = 21.6 minutes i know 1680 is equal the 'Q' in the equation of Q= mc delta T, but why 1680 is divided by 5000, and what is the meaning of 5000 kJ/ h. THX!!!

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