A) For the first question, we’re being asked to calculate the time it takes before the ice starts to melt.
So we have to calculate the amount of heat required to convert 0.570 kg of ice at -17.5 ˚C to 0.570 kg of ice at 0˚C.
Then we have to get the time to reach that amount of heat based on the heat supplied (780 J/minute).
An open container holds ice of mass 0.570 kg at a temperature of -17.5°C. The mass of the container can be ignored. Heat is supplied to the container at the constant rate of 780 J/minute. The specific heat of ice to is 2100 J/kg•K and the heat of fusion for ice is 334 x 103 J/kg.
How much time tmelts passes before the ice starts to melt?
From the time when the heating begins, how much time t rise does it take before the temperature begins to rise above 0°C?