**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 10^{3} J/kg.

How much time t_{melts} 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?